| .TH fio 1 "August 2017" "User Manual" |
| .SH NAME |
| fio \- flexible I/O tester |
| .SH SYNOPSIS |
| .B fio |
| [\fIoptions\fR] [\fIjobfile\fR]... |
| .SH DESCRIPTION |
| .B fio |
| is a tool that will spawn a number of threads or processes doing a |
| particular type of I/O action as specified by the user. |
| The typical use of fio is to write a job file matching the I/O load |
| one wants to simulate. |
| .SH OPTIONS |
| .TP |
| .BI \-\-debug \fR=\fPtype |
| Enable verbose tracing \fItype\fR of various fio actions. May be `all' for all \fItype\fRs |
| or individual types separated by a comma (e.g. `\-\-debug=file,mem' will enable |
| file and memory debugging). `help' will list all available tracing options. |
| .TP |
| .BI \-\-parse\-only |
| Parse options only, don't start any I/O. |
| .TP |
| .BI \-\-merge\-blktrace\-only |
| Merge blktraces only, don't start any I/O. |
| .TP |
| .BI \-\-output \fR=\fPfilename |
| Write output to \fIfilename\fR. |
| .TP |
| .BI \-\-output\-format \fR=\fPformat |
| Set the reporting \fIformat\fR to `normal', `terse', `json', or |
| `json+'. Multiple formats can be selected, separate by a comma. `terse' |
| is a CSV based format. `json+' is like `json', except it adds a full |
| dump of the latency buckets. |
| .TP |
| .BI \-\-bandwidth\-log |
| Generate aggregate bandwidth logs. |
| .TP |
| .BI \-\-minimal |
| Print statistics in a terse, semicolon\-delimited format. |
| .TP |
| .BI \-\-append\-terse |
| Print statistics in selected mode AND terse, semicolon\-delimited format. |
| \fBDeprecated\fR, use \fB\-\-output\-format\fR instead to select multiple formats. |
| .TP |
| .BI \-\-terse\-version \fR=\fPversion |
| Set terse \fIversion\fR output format (default `3', or `2', `4', `5'). |
| .TP |
| .BI \-\-version |
| Print version information and exit. |
| .TP |
| .BI \-\-help |
| Print a summary of the command line options and exit. |
| .TP |
| .BI \-\-cpuclock\-test |
| Perform test and validation of internal CPU clock. |
| .TP |
| .BI \-\-crctest \fR=\fP[test] |
| Test the speed of the built\-in checksumming functions. If no argument is given, |
| all of them are tested. Alternatively, a comma separated list can be passed, in which |
| case the given ones are tested. |
| .TP |
| .BI \-\-cmdhelp \fR=\fPcommand |
| Print help information for \fIcommand\fR. May be `all' for all commands. |
| .TP |
| .BI \-\-enghelp \fR=\fP[ioengine[,command]] |
| List all commands defined by \fIioengine\fR, or print help for \fIcommand\fR |
| defined by \fIioengine\fR. If no \fIioengine\fR is given, list all |
| available ioengines. |
| .TP |
| .BI \-\-showcmd \fR=\fPjobfile |
| Convert \fIjobfile\fR to a set of command\-line options. |
| .TP |
| .BI \-\-readonly |
| Turn on safety read\-only checks, preventing writes and trims. The \fB\-\-readonly\fR |
| option is an extra safety guard to prevent users from accidentally starting |
| a write or trim workload when that is not desired. Fio will only modify the |
| device under test if `rw=write/randwrite/rw/randrw/trim/randtrim/trimwrite' |
| is given. This safety net can be used as an extra precaution. |
| .TP |
| .BI \-\-eta \fR=\fPwhen |
| Specifies when real\-time ETA estimate should be printed. \fIwhen\fR may |
| be `always', `never' or `auto'. `auto' is the default, it prints ETA when |
| requested if the output is a TTY. `always' disregards the output type, and |
| prints ETA when requested. `never' never prints ETA. |
| .TP |
| .BI \-\-eta\-interval \fR=\fPtime |
| By default, fio requests client ETA status roughly every second. With this |
| option, the interval is configurable. Fio imposes a minimum allowed time to |
| avoid flooding the console, less than 250 msec is not supported. |
| .TP |
| .BI \-\-eta\-newline \fR=\fPtime |
| Force a new line for every \fItime\fR period passed. When the unit is omitted, |
| the value is interpreted in seconds. |
| .TP |
| .BI \-\-status\-interval \fR=\fPtime |
| Force a full status dump of cumulative (from job start) values at \fItime\fR |
| intervals. This option does *not* provide per-period measurements. So |
| values such as bandwidth are running averages. When the time unit is omitted, |
| \fItime\fR is interpreted in seconds. Note that using this option with |
| `\-\-output-format=json' will yield output that technically isn't valid json, |
| since the output will be collated sets of valid json. It will need to be split |
| into valid sets of json after the run. |
| .TP |
| .BI \-\-section \fR=\fPname |
| Only run specified section \fIname\fR in job file. Multiple sections can be specified. |
| The \fB\-\-section\fR option allows one to combine related jobs into one file. |
| E.g. one job file could define light, moderate, and heavy sections. Tell |
| fio to run only the "heavy" section by giving `\-\-section=heavy' |
| command line option. One can also specify the "write" operations in one |
| section and "verify" operation in another section. The \fB\-\-section\fR option |
| only applies to job sections. The reserved *global* section is always |
| parsed and used. |
| .TP |
| .BI \-\-alloc\-size \fR=\fPkb |
| Allocate additional internal smalloc pools of size \fIkb\fR in KiB. The |
| \fB\-\-alloc\-size\fR option increases shared memory set aside for use by fio. |
| If running large jobs with randommap enabled, fio can run out of memory. |
| Smalloc is an internal allocator for shared structures from a fixed size |
| memory pool and can grow to 16 pools. The pool size defaults to 16MiB. |
| NOTE: While running `.fio_smalloc.*' backing store files are visible |
| in `/tmp'. |
| .TP |
| .BI \-\-warnings\-fatal |
| All fio parser warnings are fatal, causing fio to exit with an error. |
| .TP |
| .BI \-\-max\-jobs \fR=\fPnr |
| Set the maximum number of threads/processes to support to \fInr\fR. |
| NOTE: On Linux, it may be necessary to increase the shared-memory limit |
| (`/proc/sys/kernel/shmmax') if fio runs into errors while creating jobs. |
| .TP |
| .BI \-\-server \fR=\fPargs |
| Start a backend server, with \fIargs\fR specifying what to listen to. |
| See \fBCLIENT/SERVER\fR section. |
| .TP |
| .BI \-\-daemonize \fR=\fPpidfile |
| Background a fio server, writing the pid to the given \fIpidfile\fR file. |
| .TP |
| .BI \-\-client \fR=\fPhostname |
| Instead of running the jobs locally, send and run them on the given \fIhostname\fR |
| or set of \fIhostname\fRs. See \fBCLIENT/SERVER\fR section. |
| .TP |
| .BI \-\-remote\-config \fR=\fPfile |
| Tell fio server to load this local \fIfile\fR. |
| .TP |
| .BI \-\-idle\-prof \fR=\fPoption |
| Report CPU idleness. \fIoption\fR is one of the following: |
| .RS |
| .RS |
| .TP |
| .B calibrate |
| Run unit work calibration only and exit. |
| .TP |
| .B system |
| Show aggregate system idleness and unit work. |
| .TP |
| .B percpu |
| As \fBsystem\fR but also show per CPU idleness. |
| .RE |
| .RE |
| .TP |
| .BI \-\-inflate\-log \fR=\fPlog |
| Inflate and output compressed \fIlog\fR. |
| .TP |
| .BI \-\-trigger\-file \fR=\fPfile |
| Execute trigger command when \fIfile\fR exists. |
| .TP |
| .BI \-\-trigger\-timeout \fR=\fPtime |
| Execute trigger at this \fItime\fR. |
| .TP |
| .BI \-\-trigger \fR=\fPcommand |
| Set this \fIcommand\fR as local trigger. |
| .TP |
| .BI \-\-trigger\-remote \fR=\fPcommand |
| Set this \fIcommand\fR as remote trigger. |
| .TP |
| .BI \-\-aux\-path \fR=\fPpath |
| Use the directory specified by \fIpath\fP for generated state files instead |
| of the current working directory. |
| .SH "JOB FILE FORMAT" |
| Any parameters following the options will be assumed to be job files, unless |
| they match a job file parameter. Multiple job files can be listed and each job |
| file will be regarded as a separate group. Fio will \fBstonewall\fR execution |
| between each group. |
| |
| Fio accepts one or more job files describing what it is |
| supposed to do. The job file format is the classic ini file, where the names |
| enclosed in [] brackets define the job name. You are free to use any ASCII name |
| you want, except *global* which has special meaning. Following the job name is |
| a sequence of zero or more parameters, one per line, that define the behavior of |
| the job. If the first character in a line is a ';' or a '#', the entire line is |
| discarded as a comment. |
| |
| A *global* section sets defaults for the jobs described in that file. A job may |
| override a *global* section parameter, and a job file may even have several |
| *global* sections if so desired. A job is only affected by a *global* section |
| residing above it. |
| |
| The \fB\-\-cmdhelp\fR option also lists all options. If used with an \fIcommand\fR |
| argument, \fB\-\-cmdhelp\fR will detail the given \fIcommand\fR. |
| |
| See the `examples/' directory for inspiration on how to write job files. Note |
| the copyright and license requirements currently apply to |
| `examples/' files. |
| |
| Note that the maximum length of a line in the job file is 8192 bytes. |
| .SH "JOB FILE PARAMETERS" |
| Some parameters take an option of a given type, such as an integer or a |
| string. Anywhere a numeric value is required, an arithmetic expression may be |
| used, provided it is surrounded by parentheses. Supported operators are: |
| .RS |
| .P |
| .B addition (+) |
| .P |
| .B subtraction (\-) |
| .P |
| .B multiplication (*) |
| .P |
| .B division (/) |
| .P |
| .B modulus (%) |
| .P |
| .B exponentiation (^) |
| .RE |
| .P |
| For time values in expressions, units are microseconds by default. This is |
| different than for time values not in expressions (not enclosed in |
| parentheses). |
| .SH "PARAMETER TYPES" |
| The following parameter types are used. |
| .TP |
| .I str |
| String. A sequence of alphanumeric characters. |
| .TP |
| .I time |
| Integer with possible time suffix. Without a unit value is interpreted as |
| seconds unless otherwise specified. Accepts a suffix of 'd' for days, 'h' for |
| hours, 'm' for minutes, 's' for seconds, 'ms' (or 'msec') for milliseconds and 'us' |
| (or 'usec') for microseconds. For example, use 10m for 10 minutes. |
| .TP |
| .I int |
| Integer. A whole number value, which may contain an integer prefix |
| and an integer suffix. |
| .RS |
| .RS |
| .P |
| [*integer prefix*] **number** [*integer suffix*] |
| .RE |
| .P |
| The optional *integer prefix* specifies the number's base. The default |
| is decimal. *0x* specifies hexadecimal. |
| .P |
| The optional *integer suffix* specifies the number's units, and includes an |
| optional unit prefix and an optional unit. For quantities of data, the |
| default unit is bytes. For quantities of time, the default unit is seconds |
| unless otherwise specified. |
| .P |
| With `kb_base=1000', fio follows international standards for unit |
| prefixes. To specify power-of-10 decimal values defined in the |
| International System of Units (SI): |
| .RS |
| .P |
| .PD 0 |
| K means kilo (K) or 1000 |
| .P |
| M means mega (M) or 1000**2 |
| .P |
| G means giga (G) or 1000**3 |
| .P |
| T means tera (T) or 1000**4 |
| .P |
| P means peta (P) or 1000**5 |
| .PD |
| .RE |
| .P |
| To specify power-of-2 binary values defined in IEC 80000-13: |
| .RS |
| .P |
| .PD 0 |
| Ki means kibi (Ki) or 1024 |
| .P |
| Mi means mebi (Mi) or 1024**2 |
| .P |
| Gi means gibi (Gi) or 1024**3 |
| .P |
| Ti means tebi (Ti) or 1024**4 |
| .P |
| Pi means pebi (Pi) or 1024**5 |
| .PD |
| .RE |
| .P |
| With `kb_base=1024' (the default), the unit prefixes are opposite |
| from those specified in the SI and IEC 80000-13 standards to provide |
| compatibility with old scripts. For example, 4k means 4096. |
| .P |
| For quantities of data, an optional unit of 'B' may be included |
| (e.g., 'kB' is the same as 'k'). |
| .P |
| The *integer suffix* is not case sensitive (e.g., m/mi mean mebi/mega, |
| not milli). 'b' and 'B' both mean byte, not bit. |
| .P |
| Examples with `kb_base=1000': |
| .RS |
| .P |
| .PD 0 |
| 4 KiB: 4096, 4096b, 4096B, 4k, 4kb, 4kB, 4K, 4KB |
| .P |
| 1 MiB: 1048576, 1m, 1024k |
| .P |
| 1 MB: 1000000, 1mi, 1000ki |
| .P |
| 1 TiB: 1073741824, 1t, 1024m, 1048576k |
| .P |
| 1 TB: 1000000000, 1ti, 1000mi, 1000000ki |
| .PD |
| .RE |
| .P |
| Examples with `kb_base=1024' (default): |
| .RS |
| .P |
| .PD 0 |
| 4 KiB: 4096, 4096b, 4096B, 4k, 4kb, 4kB, 4K, 4KB |
| .P |
| 1 MiB: 1048576, 1m, 1024k |
| .P |
| 1 MB: 1000000, 1mi, 1000ki |
| .P |
| 1 TiB: 1073741824, 1t, 1024m, 1048576k |
| .P |
| 1 TB: 1000000000, 1ti, 1000mi, 1000000ki |
| .PD |
| .RE |
| .P |
| To specify times (units are not case sensitive): |
| .RS |
| .P |
| .PD 0 |
| D means days |
| .P |
| H means hours |
| .P |
| M mean minutes |
| .P |
| s or sec means seconds (default) |
| .P |
| ms or msec means milliseconds |
| .P |
| us or usec means microseconds |
| .PD |
| .RE |
| .P |
| If the option accepts an upper and lower range, use a colon ':' or |
| minus '\-' to separate such values. See \fIirange\fR parameter type. |
| If the lower value specified happens to be larger than the upper value |
| the two values are swapped. |
| .RE |
| .TP |
| .I bool |
| Boolean. Usually parsed as an integer, however only defined for |
| true and false (1 and 0). |
| .TP |
| .I irange |
| Integer range with suffix. Allows value range to be given, such as |
| 1024\-4096. A colon may also be used as the separator, e.g. 1k:4k. If the |
| option allows two sets of ranges, they can be specified with a ',' or '/' |
| delimiter: 1k\-4k/8k\-32k. Also see \fIint\fR parameter type. |
| .TP |
| .I float_list |
| A list of floating point numbers, separated by a ':' character. |
| .SH "JOB PARAMETERS" |
| With the above in mind, here follows the complete list of fio job parameters. |
| .SS "Units" |
| .TP |
| .BI kb_base \fR=\fPint |
| Select the interpretation of unit prefixes in input parameters. |
| .RS |
| .RS |
| .TP |
| .B 1000 |
| Inputs comply with IEC 80000-13 and the International |
| System of Units (SI). Use: |
| .RS |
| .P |
| .PD 0 |
| \- power-of-2 values with IEC prefixes (e.g., KiB) |
| .P |
| \- power-of-10 values with SI prefixes (e.g., kB) |
| .PD |
| .RE |
| .TP |
| .B 1024 |
| Compatibility mode (default). To avoid breaking old scripts: |
| .P |
| .RS |
| .PD 0 |
| \- power-of-2 values with SI prefixes |
| .P |
| \- power-of-10 values with IEC prefixes |
| .PD |
| .RE |
| .RE |
| .P |
| See \fBbs\fR for more details on input parameters. |
| .P |
| Outputs always use correct prefixes. Most outputs include both |
| side-by-side, like: |
| .P |
| .RS |
| bw=2383.3kB/s (2327.4KiB/s) |
| .RE |
| .P |
| If only one value is reported, then kb_base selects the one to use: |
| .P |
| .RS |
| .PD 0 |
| 1000 \-\- SI prefixes |
| .P |
| 1024 \-\- IEC prefixes |
| .PD |
| .RE |
| .RE |
| .TP |
| .BI unit_base \fR=\fPint |
| Base unit for reporting. Allowed values are: |
| .RS |
| .RS |
| .TP |
| .B 0 |
| Use auto-detection (default). |
| .TP |
| .B 8 |
| Byte based. |
| .TP |
| .B 1 |
| Bit based. |
| .RE |
| .RE |
| .SS "Job description" |
| .TP |
| .BI name \fR=\fPstr |
| ASCII name of the job. This may be used to override the name printed by fio |
| for this job. Otherwise the job name is used. On the command line this |
| parameter has the special purpose of also signaling the start of a new job. |
| .TP |
| .BI description \fR=\fPstr |
| Text description of the job. Doesn't do anything except dump this text |
| description when this job is run. It's not parsed. |
| .TP |
| .BI loops \fR=\fPint |
| Run the specified number of iterations of this job. Used to repeat the same |
| workload a given number of times. Defaults to 1. |
| .TP |
| .BI numjobs \fR=\fPint |
| Create the specified number of clones of this job. Each clone of job |
| is spawned as an independent thread or process. May be used to setup a |
| larger number of threads/processes doing the same thing. Each thread is |
| reported separately; to see statistics for all clones as a whole, use |
| \fBgroup_reporting\fR in conjunction with \fBnew_group\fR. |
| See \fB\-\-max\-jobs\fR. Default: 1. |
| .SS "Time related parameters" |
| .TP |
| .BI runtime \fR=\fPtime |
| Tell fio to terminate processing after the specified period of time. It |
| can be quite hard to determine for how long a specified job will run, so |
| this parameter is handy to cap the total runtime to a given time. When |
| the unit is omitted, the value is interpreted in seconds. |
| .TP |
| .BI time_based |
| If set, fio will run for the duration of the \fBruntime\fR specified |
| even if the file(s) are completely read or written. It will simply loop over |
| the same workload as many times as the \fBruntime\fR allows. |
| .TP |
| .BI startdelay \fR=\fPirange(int) |
| Delay the start of job for the specified amount of time. Can be a single |
| value or a range. When given as a range, each thread will choose a value |
| randomly from within the range. Value is in seconds if a unit is omitted. |
| .TP |
| .BI ramp_time \fR=\fPtime |
| If set, fio will run the specified workload for this amount of time before |
| logging any performance numbers. Useful for letting performance settle |
| before logging results, thus minimizing the runtime required for stable |
| results. Note that the \fBramp_time\fR is considered lead in time for a job, |
| thus it will increase the total runtime if a special timeout or |
| \fBruntime\fR is specified. When the unit is omitted, the value is |
| given in seconds. |
| .TP |
| .BI clocksource \fR=\fPstr |
| Use the given clocksource as the base of timing. The supported options are: |
| .RS |
| .RS |
| .TP |
| .B gettimeofday |
| \fBgettimeofday\fR\|(2) |
| .TP |
| .B clock_gettime |
| \fBclock_gettime\fR\|(2) |
| .TP |
| .B cpu |
| Internal CPU clock source |
| .RE |
| .P |
| \fBcpu\fR is the preferred clocksource if it is reliable, as it is very fast (and |
| fio is heavy on time calls). Fio will automatically use this clocksource if |
| it's supported and considered reliable on the system it is running on, |
| unless another clocksource is specifically set. For x86/x86\-64 CPUs, this |
| means supporting TSC Invariant. |
| .RE |
| .TP |
| .BI gtod_reduce \fR=\fPbool |
| Enable all of the \fBgettimeofday\fR\|(2) reducing options |
| (\fBdisable_clat\fR, \fBdisable_slat\fR, \fBdisable_bw_measurement\fR) plus |
| reduce precision of the timeout somewhat to really shrink the |
| \fBgettimeofday\fR\|(2) call count. With this option enabled, we only do |
| about 0.4% of the \fBgettimeofday\fR\|(2) calls we would have done if all |
| time keeping was enabled. |
| .TP |
| .BI gtod_cpu \fR=\fPint |
| Sometimes it's cheaper to dedicate a single thread of execution to just |
| getting the current time. Fio (and databases, for instance) are very |
| intensive on \fBgettimeofday\fR\|(2) calls. With this option, you can set |
| one CPU aside for doing nothing but logging current time to a shared memory |
| location. Then the other threads/processes that run I/O workloads need only |
| copy that segment, instead of entering the kernel with a |
| \fBgettimeofday\fR\|(2) call. The CPU set aside for doing these time |
| calls will be excluded from other uses. Fio will manually clear it from the |
| CPU mask of other jobs. |
| .SS "Target file/device" |
| .TP |
| .BI directory \fR=\fPstr |
| Prefix \fBfilename\fRs with this directory. Used to place files in a different |
| location than `./'. You can specify a number of directories by |
| separating the names with a ':' character. These directories will be |
| assigned equally distributed to job clones created by \fBnumjobs\fR as |
| long as they are using generated filenames. If specific \fBfilename\fR(s) are |
| set fio will use the first listed directory, and thereby matching the |
| \fBfilename\fR semantic (which generates a file for each clone if not |
| specified, but lets all clones use the same file if set). |
| .RS |
| .P |
| See the \fBfilename\fR option for information on how to escape ':' |
| characters within the directory path itself. |
| .P |
| Note: To control the directory fio will use for internal state files |
| use \fB\-\-aux\-path\fR. |
| .RE |
| .TP |
| .BI filename \fR=\fPstr |
| Fio normally makes up a \fBfilename\fR based on the job name, thread number, and |
| file number (see \fBfilename_format\fR). If you want to share files |
| between threads in a job or several |
| jobs with fixed file paths, specify a \fBfilename\fR for each of them to override |
| the default. If the ioengine is file based, you can specify a number of files |
| by separating the names with a ':' colon. So if you wanted a job to open |
| `/dev/sda' and `/dev/sdb' as the two working files, you would use |
| `filename=/dev/sda:/dev/sdb'. This also means that whenever this option is |
| specified, \fBnrfiles\fR is ignored. The size of regular files specified |
| by this option will be \fBsize\fR divided by number of files unless an |
| explicit size is specified by \fBfilesize\fR. |
| .RS |
| .P |
| Each colon in the wanted path must be escaped with a '\\' |
| character. For instance, if the path is `/dev/dsk/foo@3,0:c' then you |
| would use `filename=/dev/dsk/foo@3,0\\:c' and if the path is |
| `F:\\filename' then you would use `filename=F\\:\\filename'. |
| .P |
| On Windows, disk devices are accessed as `\\\\.\\PhysicalDrive0' for |
| the first device, `\\\\.\\PhysicalDrive1' for the second etc. |
| Note: Windows and FreeBSD prevent write access to areas |
| of the disk containing in-use data (e.g. filesystems). |
| .P |
| The filename `\-' is a reserved name, meaning *stdin* or *stdout*. Which |
| of the two depends on the read/write direction set. |
| .RE |
| .TP |
| .BI filename_format \fR=\fPstr |
| If sharing multiple files between jobs, it is usually necessary to have fio |
| generate the exact names that you want. By default, fio will name a file |
| based on the default file format specification of |
| `jobname.jobnumber.filenumber'. With this option, that can be |
| customized. Fio will recognize and replace the following keywords in this |
| string: |
| .RS |
| .RS |
| .TP |
| .B $jobname |
| The name of the worker thread or process. |
| .TP |
| .B $jobnum |
| The incremental number of the worker thread or process. |
| .TP |
| .B $filenum |
| The incremental number of the file for that worker thread or process. |
| .RE |
| .P |
| To have dependent jobs share a set of files, this option can be set to have |
| fio generate filenames that are shared between the two. For instance, if |
| `testfiles.$filenum' is specified, file number 4 for any job will be |
| named `testfiles.4'. The default of `$jobname.$jobnum.$filenum' |
| will be used if no other format specifier is given. |
| .P |
| If you specify a path then the directories will be created up to the main |
| directory for the file. So for example if you specify `a/b/c/$jobnum` then the |
| directories a/b/c will be created before the file setup part of the job. If you |
| specify \fBdirectory\fR then the path will be relative that directory, otherwise |
| it is treated as the absolute path. |
| .RE |
| .TP |
| .BI unique_filename \fR=\fPbool |
| To avoid collisions between networked clients, fio defaults to prefixing any |
| generated filenames (with a directory specified) with the source of the |
| client connecting. To disable this behavior, set this option to 0. |
| .TP |
| .BI opendir \fR=\fPstr |
| Recursively open any files below directory \fIstr\fR. |
| .TP |
| .BI lockfile \fR=\fPstr |
| Fio defaults to not locking any files before it does I/O to them. If a file |
| or file descriptor is shared, fio can serialize I/O to that file to make the |
| end result consistent. This is usual for emulating real workloads that share |
| files. The lock modes are: |
| .RS |
| .RS |
| .TP |
| .B none |
| No locking. The default. |
| .TP |
| .B exclusive |
| Only one thread or process may do I/O at a time, excluding all others. |
| .TP |
| .B readwrite |
| Read\-write locking on the file. Many readers may |
| access the file at the same time, but writes get exclusive access. |
| .RE |
| .RE |
| .TP |
| .BI nrfiles \fR=\fPint |
| Number of files to use for this job. Defaults to 1. The size of files |
| will be \fBsize\fR divided by this unless explicit size is specified by |
| \fBfilesize\fR. Files are created for each thread separately, and each |
| file will have a file number within its name by default, as explained in |
| \fBfilename\fR section. |
| .TP |
| .BI openfiles \fR=\fPint |
| Number of files to keep open at the same time. Defaults to the same as |
| \fBnrfiles\fR, can be set smaller to limit the number simultaneous |
| opens. |
| .TP |
| .BI file_service_type \fR=\fPstr |
| Defines how fio decides which file from a job to service next. The following |
| types are defined: |
| .RS |
| .RS |
| .TP |
| .B random |
| Choose a file at random. |
| .TP |
| .B roundrobin |
| Round robin over opened files. This is the default. |
| .TP |
| .B sequential |
| Finish one file before moving on to the next. Multiple files can |
| still be open depending on \fBopenfiles\fR. |
| .TP |
| .B zipf |
| Use a Zipf distribution to decide what file to access. |
| .TP |
| .B pareto |
| Use a Pareto distribution to decide what file to access. |
| .TP |
| .B normal |
| Use a Gaussian (normal) distribution to decide what file to access. |
| .TP |
| .B gauss |
| Alias for normal. |
| .RE |
| .P |
| For \fBrandom\fR, \fBroundrobin\fR, and \fBsequential\fR, a postfix can be appended to |
| tell fio how many I/Os to issue before switching to a new file. For example, |
| specifying `file_service_type=random:8' would cause fio to issue |
| 8 I/Os before selecting a new file at random. For the non-uniform |
| distributions, a floating point postfix can be given to influence how the |
| distribution is skewed. See \fBrandom_distribution\fR for a description |
| of how that would work. |
| .RE |
| .TP |
| .BI ioscheduler \fR=\fPstr |
| Attempt to switch the device hosting the file to the specified I/O scheduler |
| before running. |
| .TP |
| .BI create_serialize \fR=\fPbool |
| If true, serialize the file creation for the jobs. This may be handy to |
| avoid interleaving of data files, which may greatly depend on the filesystem |
| used and even the number of processors in the system. Default: true. |
| .TP |
| .BI create_fsync \fR=\fPbool |
| \fBfsync\fR\|(2) the data file after creation. This is the default. |
| .TP |
| .BI create_on_open \fR=\fPbool |
| If true, don't pre-create files but allow the job's open() to create a file |
| when it's time to do I/O. Default: false \-\- pre-create all necessary files |
| when the job starts. |
| .TP |
| .BI create_only \fR=\fPbool |
| If true, fio will only run the setup phase of the job. If files need to be |
| laid out or updated on disk, only that will be done \-\- the actual job contents |
| are not executed. Default: false. |
| .TP |
| .BI allow_file_create \fR=\fPbool |
| If true, fio is permitted to create files as part of its workload. If this |
| option is false, then fio will error out if |
| the files it needs to use don't already exist. Default: true. |
| .TP |
| .BI allow_mounted_write \fR=\fPbool |
| If this isn't set, fio will abort jobs that are destructive (e.g. that write) |
| to what appears to be a mounted device or partition. This should help catch |
| creating inadvertently destructive tests, not realizing that the test will |
| destroy data on the mounted file system. Note that some platforms don't allow |
| writing against a mounted device regardless of this option. Default: false. |
| .TP |
| .BI pre_read \fR=\fPbool |
| If this is given, files will be pre-read into memory before starting the |
| given I/O operation. This will also clear the \fBinvalidate\fR flag, |
| since it is pointless to pre-read and then drop the cache. This will only |
| work for I/O engines that are seek-able, since they allow you to read the |
| same data multiple times. Thus it will not work on non-seekable I/O engines |
| (e.g. network, splice). Default: false. |
| .TP |
| .BI unlink \fR=\fPbool |
| Unlink the job files when done. Not the default, as repeated runs of that |
| job would then waste time recreating the file set again and again. Default: |
| false. |
| .TP |
| .BI unlink_each_loop \fR=\fPbool |
| Unlink job files after each iteration or loop. Default: false. |
| .TP |
| .BI zonemode \fR=\fPstr |
| Accepted values are: |
| .RS |
| .RS |
| .TP |
| .B none |
| The \fBzonerange\fR, \fBzonesize\fR \fBzonecapacity\fR and \fBzoneskip\fR |
| parameters are ignored. |
| .TP |
| .B strided |
| I/O happens in a single zone until \fBzonesize\fR bytes have been transferred. |
| After that number of bytes has been transferred processing of the next zone |
| starts. The \fBzonecapacity\fR parameter is ignored. |
| .TP |
| .B zbd |
| Zoned block device mode. I/O happens sequentially in each zone, even if random |
| I/O has been selected. Random I/O happens across all zones instead of being |
| restricted to a single zone. |
| .RE |
| .RE |
| .TP |
| .BI zonerange \fR=\fPint |
| For \fBzonemode\fR=strided, this is the size of a single zone. See also |
| \fBzonesize\fR and \fBzoneskip\fR. |
| |
| For \fBzonemode\fR=zbd, this parameter is ignored. |
| .TP |
| .BI zonesize \fR=\fPint |
| For \fBzonemode\fR=strided, this is the number of bytes to transfer before |
| skipping \fBzoneskip\fR bytes. If this parameter is smaller than |
| \fBzonerange\fR then only a fraction of each zone with \fBzonerange\fR bytes |
| will be accessed. If this parameter is larger than \fBzonerange\fR then each |
| zone will be accessed multiple times before skipping to the next zone. |
| |
| For \fBzonemode\fR=zbd, this is the size of a single zone. The |
| \fBzonerange\fR parameter is ignored in this mode. For a job accessing a |
| zoned block device, the specified \fBzonesize\fR must be 0 or equal to the |
| device zone size. For a regular block device or file, the specified |
| \fBzonesize\fR must be at least 512B. |
| .TP |
| .BI zonecapacity \fR=\fPint |
| For \fBzonemode\fR=zbd, this defines the capacity of a single zone, which is |
| the accessible area starting from the zone start address. This parameter only |
| applies when using \fBzonemode\fR=zbd in combination with regular block devices. |
| If not specified it defaults to the zone size. If the target device is a zoned |
| block device, the zone capacity is obtained from the device information and this |
| option is ignored. |
| .TP |
| .BI zoneskip \fR=\fPint |
| For \fBzonemode\fR=strided, the number of bytes to skip after \fBzonesize\fR |
| bytes of data have been transferred. |
| |
| For \fBzonemode\fR=zbd, the \fBzonesize\fR aligned number of bytes to skip |
| once a zone is fully written (write workloads) or all written data in the |
| zone have been read (read workloads). This parameter is valid only for |
| sequential workloads and ignored for random workloads. For read workloads, |
| see also \fBread_beyond_wp\fR. |
| |
| .TP |
| .BI read_beyond_wp \fR=\fPbool |
| This parameter applies to \fBzonemode=zbd\fR only. |
| |
| Zoned block devices are block devices that consist of multiple zones. Each |
| zone has a type, e.g. conventional or sequential. A conventional zone can be |
| written at any offset that is a multiple of the block size. Sequential zones |
| must be written sequentially. The position at which a write must occur is |
| called the write pointer. A zoned block device can be either host managed or |
| host aware. For host managed devices the host must ensure that writes happen |
| sequentially. Fio recognizes host managed devices and serializes writes to |
| sequential zones for these devices. |
| |
| If a read occurs in a sequential zone beyond the write pointer then the zoned |
| block device will complete the read without reading any data from the storage |
| medium. Since such reads lead to unrealistically high bandwidth and IOPS |
| numbers fio only reads beyond the write pointer if explicitly told to do |
| so. Default: false. |
| .TP |
| .BI max_open_zones \fR=\fPint |
| When running a random write test across an entire drive many more zones will be |
| open than in a typical application workload. Hence this command line option |
| that allows to limit the number of open zones. The number of open zones is |
| defined as the number of zones to which write commands are issued by all |
| threads/processes. |
| .TP |
| .BI job_max_open_zones \fR=\fPint |
| Limit on the number of simultaneously opened zones per single thread/process. |
| .TP |
| .BI zone_reset_threshold \fR=\fPfloat |
| A number between zero and one that indicates the ratio of logical blocks with |
| data to the total number of logical blocks in the test above which zones |
| should be reset periodically. |
| .TP |
| .BI zone_reset_frequency \fR=\fPfloat |
| A number between zero and one that indicates how often a zone reset should be |
| issued if the zone reset threshold has been exceeded. A zone reset is |
| submitted after each (1 / zone_reset_frequency) write requests. This and the |
| previous parameter can be used to simulate garbage collection activity. |
| |
| .SS "I/O type" |
| .TP |
| .BI direct \fR=\fPbool |
| If value is true, use non-buffered I/O. This is usually O_DIRECT. Note that |
| OpenBSD and ZFS on Solaris don't support direct I/O. On Windows the synchronous |
| ioengines don't support direct I/O. Default: false. |
| .TP |
| .BI atomic \fR=\fPbool |
| If value is true, attempt to use atomic direct I/O. Atomic writes are |
| guaranteed to be stable once acknowledged by the operating system. Only |
| Linux supports O_ATOMIC right now. |
| .TP |
| .BI buffered \fR=\fPbool |
| If value is true, use buffered I/O. This is the opposite of the |
| \fBdirect\fR option. Defaults to true. |
| .TP |
| .BI readwrite \fR=\fPstr "\fR,\fP rw" \fR=\fPstr |
| Type of I/O pattern. Accepted values are: |
| .RS |
| .RS |
| .TP |
| .B read |
| Sequential reads. |
| .TP |
| .B write |
| Sequential writes. |
| .TP |
| .B trim |
| Sequential trims (Linux block devices and SCSI character devices only). |
| .TP |
| .B randread |
| Random reads. |
| .TP |
| .B randwrite |
| Random writes. |
| .TP |
| .B randtrim |
| Random trims (Linux block devices and SCSI character devices only). |
| .TP |
| .B rw,readwrite |
| Sequential mixed reads and writes. |
| .TP |
| .B randrw |
| Random mixed reads and writes. |
| .TP |
| .B trimwrite |
| Sequential trim+write sequences. Blocks will be trimmed first, |
| then the same blocks will be written to. |
| .RE |
| .P |
| Fio defaults to read if the option is not specified. For the mixed I/O |
| types, the default is to split them 50/50. For certain types of I/O the |
| result may still be skewed a bit, since the speed may be different. |
| .P |
| It is possible to specify the number of I/Os to do before getting a new |
| offset by appending `:<nr>' to the end of the string given. For a |
| random read, it would look like `rw=randread:8' for passing in an offset |
| modifier with a value of 8. If the suffix is used with a sequential I/O |
| pattern, then the `<nr>' value specified will be added to the generated |
| offset for each I/O turning sequential I/O into sequential I/O with holes. |
| For instance, using `rw=write:4k' will skip 4k for every write. Also see |
| the \fBrw_sequencer\fR option. |
| .RE |
| .TP |
| .BI rw_sequencer \fR=\fPstr |
| If an offset modifier is given by appending a number to the `rw=\fIstr\fR' |
| line, then this option controls how that number modifies the I/O offset |
| being generated. Accepted values are: |
| .RS |
| .RS |
| .TP |
| .B sequential |
| Generate sequential offset. |
| .TP |
| .B identical |
| Generate the same offset. |
| .RE |
| .P |
| \fBsequential\fR is only useful for random I/O, where fio would normally |
| generate a new random offset for every I/O. If you append e.g. 8 to randread, |
| you would get a new random offset for every 8 I/Os. The result would be a |
| seek for only every 8 I/Os, instead of for every I/O. Use `rw=randread:8' |
| to specify that. As sequential I/O is already sequential, setting |
| \fBsequential\fR for that would not result in any differences. \fBidentical\fR |
| behaves in a similar fashion, except it sends the same offset 8 number of |
| times before generating a new offset. |
| .RE |
| .TP |
| .BI unified_rw_reporting \fR=\fPbool |
| Fio normally reports statistics on a per data direction basis, meaning that |
| reads, writes, and trims are accounted and reported separately. If this |
| option is set fio sums the results and report them as "mixed" instead. |
| .TP |
| .BI randrepeat \fR=\fPbool |
| Seed the random number generator used for random I/O patterns in a |
| predictable way so the pattern is repeatable across runs. Default: true. |
| .TP |
| .BI allrandrepeat \fR=\fPbool |
| Seed all random number generators in a predictable way so results are |
| repeatable across runs. Default: false. |
| .TP |
| .BI randseed \fR=\fPint |
| Seed the random number generators based on this seed value, to be able to |
| control what sequence of output is being generated. If not set, the random |
| sequence depends on the \fBrandrepeat\fR setting. |
| .TP |
| .BI fallocate \fR=\fPstr |
| Whether pre-allocation is performed when laying down files. |
| Accepted values are: |
| .RS |
| .RS |
| .TP |
| .B none |
| Do not pre-allocate space. |
| .TP |
| .B native |
| Use a platform's native pre-allocation call but fall back to |
| \fBnone\fR behavior if it fails/is not implemented. |
| .TP |
| .B posix |
| Pre-allocate via \fBposix_fallocate\fR\|(3). |
| .TP |
| .B keep |
| Pre-allocate via \fBfallocate\fR\|(2) with |
| FALLOC_FL_KEEP_SIZE set. |
| .TP |
| .B truncate |
| Extend file to final size using \fBftruncate\fR|(2) |
| instead of allocating. |
| .TP |
| .B 0 |
| Backward-compatible alias for \fBnone\fR. |
| .TP |
| .B 1 |
| Backward-compatible alias for \fBposix\fR. |
| .RE |
| .P |
| May not be available on all supported platforms. \fBkeep\fR is only available |
| on Linux. If using ZFS on Solaris this cannot be set to \fBposix\fR |
| because ZFS doesn't support pre-allocation. Default: \fBnative\fR if any |
| pre-allocation methods except \fBtruncate\fR are available, \fBnone\fR if not. |
| .P |
| Note that using \fBtruncate\fR on Windows will interact surprisingly |
| with non-sequential write patterns. When writing to a file that has |
| been extended by setting the end-of-file information, Windows will |
| backfill the unwritten portion of the file up to that offset with |
| zeroes before issuing the new write. This means that a single small |
| write to the end of an extended file will stall until the entire |
| file has been filled with zeroes. |
| .RE |
| .TP |
| .BI fadvise_hint \fR=\fPstr |
| Use \fBposix_fadvise\fR\|(2) or \fBposix_madvise\fR\|(2) to advise the kernel |
| what I/O patterns are likely to be issued. Accepted values are: |
| .RS |
| .RS |
| .TP |
| .B 0 |
| Backwards compatible hint for "no hint". |
| .TP |
| .B 1 |
| Backwards compatible hint for "advise with fio workload type". This |
| uses FADV_RANDOM for a random workload, and FADV_SEQUENTIAL |
| for a sequential workload. |
| .TP |
| .B sequential |
| Advise using FADV_SEQUENTIAL. |
| .TP |
| .B random |
| Advise using FADV_RANDOM. |
| .RE |
| .RE |
| .TP |
| .BI write_hint \fR=\fPstr |
| Use \fBfcntl\fR\|(2) to advise the kernel what life time to expect |
| from a write. Only supported on Linux, as of version 4.13. Accepted |
| values are: |
| .RS |
| .RS |
| .TP |
| .B none |
| No particular life time associated with this file. |
| .TP |
| .B short |
| Data written to this file has a short life time. |
| .TP |
| .B medium |
| Data written to this file has a medium life time. |
| .TP |
| .B long |
| Data written to this file has a long life time. |
| .TP |
| .B extreme |
| Data written to this file has a very long life time. |
| .RE |
| .P |
| The values are all relative to each other, and no absolute meaning |
| should be associated with them. |
| .RE |
| .TP |
| .BI offset \fR=\fPint |
| Start I/O at the provided offset in the file, given as either a fixed size in |
| bytes or a percentage. If a percentage is given, the generated offset will be |
| aligned to the minimum \fBblocksize\fR or to the value of \fBoffset_align\fR if |
| provided. Data before the given offset will not be touched. This |
| effectively caps the file size at `real_size \- offset'. Can be combined with |
| \fBsize\fR to constrain the start and end range of the I/O workload. |
| A percentage can be specified by a number between 1 and 100 followed by '%', |
| for example, `offset=20%' to specify 20%. |
| .TP |
| .BI offset_align \fR=\fPint |
| If set to non-zero value, the byte offset generated by a percentage \fBoffset\fR |
| is aligned upwards to this value. Defaults to 0 meaning that a percentage |
| offset is aligned to the minimum block size. |
| .TP |
| .BI offset_increment \fR=\fPint |
| If this is provided, then the real offset becomes `\fBoffset\fR + \fBoffset_increment\fR |
| * thread_number', where the thread number is a counter that starts at 0 and |
| is incremented for each sub-job (i.e. when \fBnumjobs\fR option is |
| specified). This option is useful if there are several jobs which are |
| intended to operate on a file in parallel disjoint segments, with even |
| spacing between the starting points. Percentages can be used for this option. |
| If a percentage is given, the generated offset will be aligned to the minimum |
| \fBblocksize\fR or to the value of \fBoffset_align\fR if provided. |
| .TP |
| .BI number_ios \fR=\fPint |
| Fio will normally perform I/Os until it has exhausted the size of the region |
| set by \fBsize\fR, or if it exhaust the allocated time (or hits an error |
| condition). With this setting, the range/size can be set independently of |
| the number of I/Os to perform. When fio reaches this number, it will exit |
| normally and report status. Note that this does not extend the amount of I/O |
| that will be done, it will only stop fio if this condition is met before |
| other end-of-job criteria. |
| .TP |
| .BI fsync \fR=\fPint |
| If writing to a file, issue an \fBfsync\fR\|(2) (or its equivalent) of |
| the dirty data for every number of blocks given. For example, if you give 32 |
| as a parameter, fio will sync the file after every 32 writes issued. If fio is |
| using non-buffered I/O, we may not sync the file. The exception is the sg |
| I/O engine, which synchronizes the disk cache anyway. Defaults to 0, which |
| means fio does not periodically issue and wait for a sync to complete. Also |
| see \fBend_fsync\fR and \fBfsync_on_close\fR. |
| .TP |
| .BI fdatasync \fR=\fPint |
| Like \fBfsync\fR but uses \fBfdatasync\fR\|(2) to only sync data and |
| not metadata blocks. In Windows, FreeBSD, DragonFlyBSD or OSX there is no |
| \fBfdatasync\fR\|(2) so this falls back to using \fBfsync\fR\|(2). |
| Defaults to 0, which means fio does not periodically issue and wait for a |
| data-only sync to complete. |
| .TP |
| .BI write_barrier \fR=\fPint |
| Make every N\-th write a barrier write. |
| .TP |
| .BI sync_file_range \fR=\fPstr:int |
| Use \fBsync_file_range\fR\|(2) for every \fIint\fR number of write |
| operations. Fio will track range of writes that have happened since the last |
| \fBsync_file_range\fR\|(2) call. \fIstr\fR can currently be one or more of: |
| .RS |
| .RS |
| .TP |
| .B wait_before |
| SYNC_FILE_RANGE_WAIT_BEFORE |
| .TP |
| .B write |
| SYNC_FILE_RANGE_WRITE |
| .TP |
| .B wait_after |
| SYNC_FILE_RANGE_WRITE_AFTER |
| .RE |
| .P |
| So if you do `sync_file_range=wait_before,write:8', fio would use |
| `SYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE' for every 8 |
| writes. Also see the \fBsync_file_range\fR\|(2) man page. This option is |
| Linux specific. |
| .RE |
| .TP |
| .BI overwrite \fR=\fPbool |
| If true, writes to a file will always overwrite existing data. If the file |
| doesn't already exist, it will be created before the write phase begins. If |
| the file exists and is large enough for the specified write phase, nothing |
| will be done. Default: false. |
| .TP |
| .BI end_fsync \fR=\fPbool |
| If true, \fBfsync\fR\|(2) file contents when a write stage has completed. |
| Default: false. |
| .TP |
| .BI fsync_on_close \fR=\fPbool |
| If true, fio will \fBfsync\fR\|(2) a dirty file on close. This differs |
| from \fBend_fsync\fR in that it will happen on every file close, not |
| just at the end of the job. Default: false. |
| .TP |
| .BI rwmixread \fR=\fPint |
| Percentage of a mixed workload that should be reads. Default: 50. |
| .TP |
| .BI rwmixwrite \fR=\fPint |
| Percentage of a mixed workload that should be writes. If both |
| \fBrwmixread\fR and \fBrwmixwrite\fR is given and the values do not |
| add up to 100%, the latter of the two will be used to override the |
| first. This may interfere with a given rate setting, if fio is asked to |
| limit reads or writes to a certain rate. If that is the case, then the |
| distribution may be skewed. Default: 50. |
| .TP |
| .BI random_distribution \fR=\fPstr:float[,str:float][,str:float] |
| By default, fio will use a completely uniform random distribution when asked |
| to perform random I/O. Sometimes it is useful to skew the distribution in |
| specific ways, ensuring that some parts of the data is more hot than others. |
| fio includes the following distribution models: |
| .RS |
| .RS |
| .TP |
| .B random |
| Uniform random distribution |
| .TP |
| .B zipf |
| Zipf distribution |
| .TP |
| .B pareto |
| Pareto distribution |
| .TP |
| .B normal |
| Normal (Gaussian) distribution |
| .TP |
| .B zoned |
| Zoned random distribution |
| .B zoned_abs |
| Zoned absolute random distribution |
| .RE |
| .P |
| When using a \fBzipf\fR or \fBpareto\fR distribution, an input value is also |
| needed to define the access pattern. For \fBzipf\fR, this is the `Zipf theta'. |
| For \fBpareto\fR, it's the `Pareto power'. Fio includes a test |
| program, \fBfio\-genzipf\fR, that can be used visualize what the given input |
| values will yield in terms of hit rates. If you wanted to use \fBzipf\fR with |
| a `theta' of 1.2, you would use `random_distribution=zipf:1.2' as the |
| option. If a non\-uniform model is used, fio will disable use of the random |
| map. For the \fBnormal\fR distribution, a normal (Gaussian) deviation is |
| supplied as a value between 0 and 100. |
| .P |
| For a \fBzoned\fR distribution, fio supports specifying percentages of I/O |
| access that should fall within what range of the file or device. For |
| example, given a criteria of: |
| .RS |
| .P |
| .PD 0 |
| 60% of accesses should be to the first 10% |
| .P |
| 30% of accesses should be to the next 20% |
| .P |
| 8% of accesses should be to the next 30% |
| .P |
| 2% of accesses should be to the next 40% |
| .PD |
| .RE |
| .P |
| we can define that through zoning of the random accesses. For the above |
| example, the user would do: |
| .RS |
| .P |
| random_distribution=zoned:60/10:30/20:8/30:2/40 |
| .RE |
| .P |
| A \fBzoned_abs\fR distribution works exactly like the\fBzoned\fR, except that |
| it takes absolute sizes. For example, let's say you wanted to define access |
| according to the following criteria: |
| .RS |
| .P |
| .PD 0 |
| 60% of accesses should be to the first 20G |
| .P |
| 30% of accesses should be to the next 100G |
| .P |
| 10% of accesses should be to the next 500G |
| .PD |
| .RE |
| .P |
| we can define an absolute zoning distribution with: |
| .RS |
| .P |
| random_distribution=zoned:60/10:30/20:8/30:2/40 |
| .RE |
| .P |
| For both \fBzoned\fR and \fBzoned_abs\fR, fio supports defining up to 256 |
| separate zones. |
| .P |
| Similarly to how \fBbssplit\fR works for setting ranges and percentages |
| of block sizes. Like \fBbssplit\fR, it's possible to specify separate |
| zones for reads, writes, and trims. If just one set is given, it'll apply to |
| all of them. |
| .RE |
| .TP |
| .BI percentage_random \fR=\fPint[,int][,int] |
| For a random workload, set how big a percentage should be random. This |
| defaults to 100%, in which case the workload is fully random. It can be set |
| from anywhere from 0 to 100. Setting it to 0 would make the workload fully |
| sequential. Any setting in between will result in a random mix of sequential |
| and random I/O, at the given percentages. Comma-separated values may be |
| specified for reads, writes, and trims as described in \fBblocksize\fR. |
| .TP |
| .BI norandommap |
| Normally fio will cover every block of the file when doing random I/O. If |
| this option is given, fio will just get a new random offset without looking |
| at past I/O history. This means that some blocks may not be read or written, |
| and that some blocks may be read/written more than once. If this option is |
| used with \fBverify\fR and multiple blocksizes (via \fBbsrange\fR), |
| only intact blocks are verified, i.e., partially-overwritten blocks are |
| ignored. With an async I/O engine and an I/O depth > 1, it is possible for |
| the same block to be overwritten, which can cause verification errors. Either |
| do not use norandommap in this case, or also use the lfsr random generator. |
| .TP |
| .BI softrandommap \fR=\fPbool |
| See \fBnorandommap\fR. If fio runs with the random block map enabled and |
| it fails to allocate the map, if this option is set it will continue without |
| a random block map. As coverage will not be as complete as with random maps, |
| this option is disabled by default. |
| .TP |
| .BI random_generator \fR=\fPstr |
| Fio supports the following engines for generating I/O offsets for random I/O: |
| .RS |
| .RS |
| .TP |
| .B tausworthe |
| Strong 2^88 cycle random number generator. |
| .TP |
| .B lfsr |
| Linear feedback shift register generator. |
| .TP |
| .B tausworthe64 |
| Strong 64\-bit 2^258 cycle random number generator. |
| .RE |
| .P |
| \fBtausworthe\fR is a strong random number generator, but it requires tracking |
| on the side if we want to ensure that blocks are only read or written |
| once. \fBlfsr\fR guarantees that we never generate the same offset twice, and |
| it's also less computationally expensive. It's not a true random generator, |
| however, though for I/O purposes it's typically good enough. \fBlfsr\fR only |
| works with single block sizes, not with workloads that use multiple block |
| sizes. If used with such a workload, fio may read or write some blocks |
| multiple times. The default value is \fBtausworthe\fR, unless the required |
| space exceeds 2^32 blocks. If it does, then \fBtausworthe64\fR is |
| selected automatically. |
| .RE |
| .SS "Block size" |
| .TP |
| .BI blocksize \fR=\fPint[,int][,int] "\fR,\fB bs" \fR=\fPint[,int][,int] |
| The block size in bytes used for I/O units. Default: 4096. A single value |
| applies to reads, writes, and trims. Comma-separated values may be |
| specified for reads, writes, and trims. A value not terminated in a comma |
| applies to subsequent types. Examples: |
| .RS |
| .RS |
| .P |
| .PD 0 |
| bs=256k means 256k for reads, writes and trims. |
| .P |
| bs=8k,32k means 8k for reads, 32k for writes and trims. |
| .P |
| bs=8k,32k, means 8k for reads, 32k for writes, and default for trims. |
| .P |
| bs=,8k means default for reads, 8k for writes and trims. |
| .P |
| bs=,8k, means default for reads, 8k for writes, and default for trims. |
| .PD |
| .RE |
| .RE |
| .TP |
| .BI blocksize_range \fR=\fPirange[,irange][,irange] "\fR,\fB bsrange" \fR=\fPirange[,irange][,irange] |
| A range of block sizes in bytes for I/O units. The issued I/O unit will |
| always be a multiple of the minimum size, unless |
| \fBblocksize_unaligned\fR is set. |
| Comma-separated ranges may be specified for reads, writes, and trims as |
| described in \fBblocksize\fR. Example: |
| .RS |
| .RS |
| .P |
| bsrange=1k\-4k,2k\-8k |
| .RE |
| .RE |
| .TP |
| .BI bssplit \fR=\fPstr[,str][,str] |
| Sometimes you want even finer grained control of the block sizes issued, not |
| just an even split between them. This option allows you to weight various |
| block sizes, so that you are able to define a specific amount of block sizes |
| issued. The format for this option is: |
| .RS |
| .RS |
| .P |
| bssplit=blocksize/percentage:blocksize/percentage |
| .RE |
| .P |
| for as many block sizes as needed. So if you want to define a workload that |
| has 50% 64k blocks, 10% 4k blocks, and 40% 32k blocks, you would write: |
| .RS |
| .P |
| bssplit=4k/10:64k/50:32k/40 |
| .RE |
| .P |
| Ordering does not matter. If the percentage is left blank, fio will fill in |
| the remaining values evenly. So a bssplit option like this one: |
| .RS |
| .P |
| bssplit=4k/50:1k/:32k/ |
| .RE |
| .P |
| would have 50% 4k ios, and 25% 1k and 32k ios. The percentages always add up |
| to 100, if bssplit is given a range that adds up to more, it will error out. |
| .P |
| Comma-separated values may be specified for reads, writes, and trims as |
| described in \fBblocksize\fR. |
| .P |
| If you want a workload that has 50% 2k reads and 50% 4k reads, while having |
| 90% 4k writes and 10% 8k writes, you would specify: |
| .RS |
| .P |
| bssplit=2k/50:4k/50,4k/90:8k/10 |
| .RE |
| .P |
| Fio supports defining up to 64 different weights for each data direction. |
| .RE |
| .TP |
| .BI blocksize_unaligned "\fR,\fB bs_unaligned" |
| If set, fio will issue I/O units with any size within |
| \fBblocksize_range\fR, not just multiples of the minimum size. This |
| typically won't work with direct I/O, as that normally requires sector |
| alignment. |
| .TP |
| .BI bs_is_seq_rand \fR=\fPbool |
| If this option is set, fio will use the normal read,write blocksize settings |
| as sequential,random blocksize settings instead. Any random read or write |
| will use the WRITE blocksize settings, and any sequential read or write will |
| use the READ blocksize settings. |
| .TP |
| .BI blockalign \fR=\fPint[,int][,int] "\fR,\fB ba" \fR=\fPint[,int][,int] |
| Boundary to which fio will align random I/O units. Default: |
| \fBblocksize\fR. Minimum alignment is typically 512b for using direct |
| I/O, though it usually depends on the hardware block size. This option is |
| mutually exclusive with using a random map for files, so it will turn off |
| that option. Comma-separated values may be specified for reads, writes, and |
| trims as described in \fBblocksize\fR. |
| .SS "Buffers and memory" |
| .TP |
| .BI zero_buffers |
| Initialize buffers with all zeros. Default: fill buffers with random data. |
| .TP |
| .BI refill_buffers |
| If this option is given, fio will refill the I/O buffers on every |
| submit. The default is to only fill it at init time and reuse that |
| data. Only makes sense if zero_buffers isn't specified, naturally. If data |
| verification is enabled, \fBrefill_buffers\fR is also automatically enabled. |
| .TP |
| .BI scramble_buffers \fR=\fPbool |
| If \fBrefill_buffers\fR is too costly and the target is using data |
| deduplication, then setting this option will slightly modify the I/O buffer |
| contents to defeat normal de-dupe attempts. This is not enough to defeat |
| more clever block compression attempts, but it will stop naive dedupe of |
| blocks. Default: true. |
| .TP |
| .BI buffer_compress_percentage \fR=\fPint |
| If this is set, then fio will attempt to provide I/O buffer content |
| (on WRITEs) that compresses to the specified level. Fio does this by |
| providing a mix of random data followed by fixed pattern data. The |
| fixed pattern is either zeros, or the pattern specified by |
| \fBbuffer_pattern\fR. If the \fBbuffer_pattern\fR option is used, it |
| might skew the compression ratio slightly. Setting |
| \fBbuffer_compress_percentage\fR to a value other than 100 will also |
| enable \fBrefill_buffers\fR in order to reduce the likelihood that |
| adjacent blocks are so similar that they over compress when seen |
| together. See \fBbuffer_compress_chunk\fR for how to set a finer or |
| coarser granularity of the random/fixed data regions. Defaults to unset |
| i.e., buffer data will not adhere to any compression level. |
| .TP |
| .BI buffer_compress_chunk \fR=\fPint |
| This setting allows fio to manage how big the random/fixed data region |
| is when using \fBbuffer_compress_percentage\fR. When |
| \fBbuffer_compress_chunk\fR is set to some non-zero value smaller than the |
| block size, fio can repeat the random/fixed region throughout the I/O |
| buffer at the specified interval (which particularly useful when |
| bigger block sizes are used for a job). When set to 0, fio will use a |
| chunk size that matches the block size resulting in a single |
| random/fixed region within the I/O buffer. Defaults to 512. When the |
| unit is omitted, the value is interpreted in bytes. |
| .TP |
| .BI buffer_pattern \fR=\fPstr |
| If set, fio will fill the I/O buffers with this pattern or with the contents |
| of a file. If not set, the contents of I/O buffers are defined by the other |
| options related to buffer contents. The setting can be any pattern of bytes, |
| and can be prefixed with 0x for hex values. It may also be a string, where |
| the string must then be wrapped with "". Or it may also be a filename, |
| where the filename must be wrapped with '' in which case the file is |
| opened and read. Note that not all the file contents will be read if that |
| would cause the buffers to overflow. So, for example: |
| .RS |
| .RS |
| .P |
| .PD 0 |
| buffer_pattern='filename' |
| .P |
| or: |
| .P |
| buffer_pattern="abcd" |
| .P |
| or: |
| .P |
| buffer_pattern=\-12 |
| .P |
| or: |
| .P |
| buffer_pattern=0xdeadface |
| .PD |
| .RE |
| .P |
| Also you can combine everything together in any order: |
| .RS |
| .P |
| buffer_pattern=0xdeadface"abcd"\-12'filename' |
| .RE |
| .RE |
| .TP |
| .BI dedupe_percentage \fR=\fPint |
| If set, fio will generate this percentage of identical buffers when |
| writing. These buffers will be naturally dedupable. The contents of the |
| buffers depend on what other buffer compression settings have been set. It's |
| possible to have the individual buffers either fully compressible, or not at |
| all \-\- this option only controls the distribution of unique buffers. Setting |
| this option will also enable \fBrefill_buffers\fR to prevent every buffer |
| being identical. |
| .TP |
| .BI invalidate \fR=\fPbool |
| Invalidate the buffer/page cache parts of the files to be used prior to |
| starting I/O if the platform and file type support it. Defaults to true. |
| This will be ignored if \fBpre_read\fR is also specified for the |
| same job. |
| .TP |
| .BI sync \fR=\fPstr |
| Whether, and what type, of synchronous I/O to use for writes. The allowed |
| values are: |
| .RS |
| .RS |
| .TP |
| .B none |
| Do not use synchronous IO, the default. |
| .TP |
| .B 0 |
| Same as \fBnone\fR. |
| .TP |
| .B sync |
| Use synchronous file IO. For the majority of I/O engines, |
| this means using O_SYNC. |
| .TP |
| .B 1 |
| Same as \fBsync\fR. |
| .TP |
| .B dsync |
| Use synchronous data IO. For the majority of I/O engines, |
| this means using O_DSYNC. |
| .PD |
| .RE |
| .RE |
| .TP |
| .BI iomem \fR=\fPstr "\fR,\fP mem" \fR=\fPstr |
| Fio can use various types of memory as the I/O unit buffer. The allowed |
| values are: |
| .RS |
| .RS |
| .TP |
| .B malloc |
| Use memory from \fBmalloc\fR\|(3) as the buffers. Default memory type. |
| .TP |
| .B shm |
| Use shared memory as the buffers. Allocated through \fBshmget\fR\|(2). |
| .TP |
| .B shmhuge |
| Same as \fBshm\fR, but use huge pages as backing. |
| .TP |
| .B mmap |
| Use \fBmmap\fR\|(2) to allocate buffers. May either be anonymous memory, or can |
| be file backed if a filename is given after the option. The format |
| is `mem=mmap:/path/to/file'. |
| .TP |
| .B mmaphuge |
| Use a memory mapped huge file as the buffer backing. Append filename |
| after mmaphuge, ala `mem=mmaphuge:/hugetlbfs/file'. |
| .TP |
| .B mmapshared |
| Same as \fBmmap\fR, but use a MMAP_SHARED mapping. |
| .TP |
| .B cudamalloc |
| Use GPU memory as the buffers for GPUDirect RDMA benchmark. |
| The \fBioengine\fR must be \fBrdma\fR. |
| .RE |
| .P |
| The area allocated is a function of the maximum allowed bs size for the job, |
| multiplied by the I/O depth given. Note that for \fBshmhuge\fR and |
| \fBmmaphuge\fR to work, the system must have free huge pages allocated. This |
| can normally be checked and set by reading/writing |
| `/proc/sys/vm/nr_hugepages' on a Linux system. Fio assumes a huge page |
| is 4MiB in size. So to calculate the number of huge pages you need for a |
| given job file, add up the I/O depth of all jobs (normally one unless |
| \fBiodepth\fR is used) and multiply by the maximum bs set. Then divide |
| that number by the huge page size. You can see the size of the huge pages in |
| `/proc/meminfo'. If no huge pages are allocated by having a non-zero |
| number in `nr_hugepages', using \fBmmaphuge\fR or \fBshmhuge\fR will fail. Also |
| see \fBhugepage\-size\fR. |
| .P |
| \fBmmaphuge\fR also needs to have hugetlbfs mounted and the file location |
| should point there. So if it's mounted in `/huge', you would use |
| `mem=mmaphuge:/huge/somefile'. |
| .RE |
| .TP |
| .BI iomem_align \fR=\fPint "\fR,\fP mem_align" \fR=\fPint |
| This indicates the memory alignment of the I/O memory buffers. Note that |
| the given alignment is applied to the first I/O unit buffer, if using |
| \fBiodepth\fR the alignment of the following buffers are given by the |
| \fBbs\fR used. In other words, if using a \fBbs\fR that is a |
| multiple of the page sized in the system, all buffers will be aligned to |
| this value. If using a \fBbs\fR that is not page aligned, the alignment |
| of subsequent I/O memory buffers is the sum of the \fBiomem_align\fR and |
| \fBbs\fR used. |
| .TP |
| .BI hugepage\-size \fR=\fPint |
| Defines the size of a huge page. Must at least be equal to the system |
| setting, see `/proc/meminfo'. Defaults to 4MiB. Should probably |
| always be a multiple of megabytes, so using `hugepage\-size=Xm' is the |
| preferred way to set this to avoid setting a non-pow-2 bad value. |
| .TP |
| .BI lockmem \fR=\fPint |
| Pin the specified amount of memory with \fBmlock\fR\|(2). Can be used to |
| simulate a smaller amount of memory. The amount specified is per worker. |
| .SS "I/O size" |
| .TP |
| .BI size \fR=\fPint |
| The total size of file I/O for each thread of this job. Fio will run until |
| this many bytes has been transferred, unless runtime is limited by other options |
| (such as \fBruntime\fR, for instance, or increased/decreased by \fBio_size\fR). |
| Fio will divide this size between the available files determined by options |
| such as \fBnrfiles\fR, \fBfilename\fR, unless \fBfilesize\fR is |
| specified by the job. If the result of division happens to be 0, the size is |
| set to the physical size of the given files or devices if they exist. |
| If this option is not specified, fio will use the full size of the given |
| files or devices. If the files do not exist, size must be given. It is also |
| possible to give size as a percentage between 1 and 100. If `size=20%' is |
| given, fio will use 20% of the full size of the given files or devices. |
| Can be combined with \fBoffset\fR to constrain the start and end range |
| that I/O will be done within. |
| .TP |
| .BI io_size \fR=\fPint "\fR,\fB io_limit" \fR=\fPint |
| Normally fio operates within the region set by \fBsize\fR, which means |
| that the \fBsize\fR option sets both the region and size of I/O to be |
| performed. Sometimes that is not what you want. With this option, it is |
| possible to define just the amount of I/O that fio should do. For instance, |
| if \fBsize\fR is set to 20GiB and \fBio_size\fR is set to 5GiB, fio |
| will perform I/O within the first 20GiB but exit when 5GiB have been |
| done. The opposite is also possible \-\- if \fBsize\fR is set to 20GiB, |
| and \fBio_size\fR is set to 40GiB, then fio will do 40GiB of I/O within |
| the 0..20GiB region. Value can be set as percentage: \fBio_size\fR=N%. |
| In this case \fBio_size\fR multiplies \fBsize\fR= value. |
| .TP |
| .BI filesize \fR=\fPirange(int) |
| Individual file sizes. May be a range, in which case fio will select sizes |
| for files at random within the given range and limited to \fBsize\fR in |
| total (if that is given). If not given, each created file is the same size. |
| This option overrides \fBsize\fR in terms of file size, which means |
| this value is used as a fixed size or possible range of each file. |
| .TP |
| .BI file_append \fR=\fPbool |
| Perform I/O after the end of the file. Normally fio will operate within the |
| size of a file. If this option is set, then fio will append to the file |
| instead. This has identical behavior to setting \fBoffset\fR to the size |
| of a file. This option is ignored on non-regular files. |
| .TP |
| .BI fill_device \fR=\fPbool "\fR,\fB fill_fs" \fR=\fPbool |
| Sets size to something really large and waits for ENOSPC (no space left on |
| device) as the terminating condition. Only makes sense with sequential |
| write. For a read workload, the mount point will be filled first then I/O |
| started on the result. This option doesn't make sense if operating on a raw |
| device node, since the size of that is already known by the file system. |
| Additionally, writing beyond end-of-device will not return ENOSPC there. |
| .SS "I/O engine" |
| .TP |
| .BI ioengine \fR=\fPstr |
| Defines how the job issues I/O to the file. The following types are defined: |
| .RS |
| .RS |
| .TP |
| .B sync |
| Basic \fBread\fR\|(2) or \fBwrite\fR\|(2) |
| I/O. \fBlseek\fR\|(2) is used to position the I/O location. |
| See \fBfsync\fR and \fBfdatasync\fR for syncing write I/Os. |
| .TP |
| .B psync |
| Basic \fBpread\fR\|(2) or \fBpwrite\fR\|(2) I/O. Default on |
| all supported operating systems except for Windows. |
| .TP |
| .B vsync |
| Basic \fBreadv\fR\|(2) or \fBwritev\fR\|(2) I/O. Will emulate |
| queuing by coalescing adjacent I/Os into a single submission. |
| .TP |
| .B pvsync |
| Basic \fBpreadv\fR\|(2) or \fBpwritev\fR\|(2) I/O. |
| .TP |
| .B pvsync2 |
| Basic \fBpreadv2\fR\|(2) or \fBpwritev2\fR\|(2) I/O. |
| .TP |
| .B libaio |
| Linux native asynchronous I/O. Note that Linux may only support |
| queued behavior with non-buffered I/O (set `direct=1' or |
| `buffered=0'). |
| This engine defines engine specific options. |
| .TP |
| .B posixaio |
| POSIX asynchronous I/O using \fBaio_read\fR\|(3) and |
| \fBaio_write\fR\|(3). |
| .TP |
| .B solarisaio |
| Solaris native asynchronous I/O. |
| .TP |
| .B windowsaio |
| Windows native asynchronous I/O. Default on Windows. |
| .TP |
| .B mmap |
| File is memory mapped with \fBmmap\fR\|(2) and data copied |
| to/from using \fBmemcpy\fR\|(3). |
| .TP |
| .B splice |
| \fBsplice\fR\|(2) is used to transfer the data and |
| \fBvmsplice\fR\|(2) to transfer data from user space to the |
| kernel. |
| .TP |
| .B sg |
| SCSI generic sg v3 I/O. May either be synchronous using the SG_IO |
| ioctl, or if the target is an sg character device we use |
| \fBread\fR\|(2) and \fBwrite\fR\|(2) for asynchronous |
| I/O. Requires \fBfilename\fR option to specify either block or |
| character devices. This engine supports trim operations. The |
| sg engine includes engine specific options. |
| .TP |
| .B libzbc |
| Synchronous I/O engine for SMR hard-disks using the \fBlibzbc\fR |
| library. The target can be either an sg character device or |
| a block device file. This engine supports the zonemode=zbd zone |
| operations. |
| .TP |
| .B null |
| Doesn't transfer any data, just pretends to. This is mainly used to |
| exercise fio itself and for debugging/testing purposes. |
| .TP |
| .B net |
| Transfer over the network to given `host:port'. Depending on the |
| \fBprotocol\fR used, the \fBhostname\fR, \fBport\fR, |
| \fBlisten\fR and \fBfilename\fR options are used to specify |
| what sort of connection to make, while the \fBprotocol\fR option |
| determines which protocol will be used. This engine defines engine |
| specific options. |
| .TP |
| .B netsplice |
| Like \fBnet\fR, but uses \fBsplice\fR\|(2) and |
| \fBvmsplice\fR\|(2) to map data and send/receive. |
| This engine defines engine specific options. |
| .TP |
| .B cpuio |
| Doesn't transfer any data, but burns CPU cycles according to the |
| \fBcpuload\fR and \fBcpuchunks\fR options. Setting |
| \fBcpuload\fR\=85 will cause that job to do nothing but burn 85% |
| of the CPU. In case of SMP machines, use `numjobs=<nr_of_cpu>' |
| to get desired CPU usage, as the cpuload only loads a |
| single CPU at the desired rate. A job never finishes unless there is |
| at least one non-cpuio job. |
| .TP |
| .B rdma |
| The RDMA I/O engine supports both RDMA memory semantics |
| (RDMA_WRITE/RDMA_READ) and channel semantics (Send/Recv) for the |
| InfiniBand, RoCE and iWARP protocols. This engine defines engine |
| specific options. |
| .TP |
| .B falloc |
| I/O engine that does regular fallocate to simulate data transfer as |
| fio ioengine. |
| .RS |
| .P |
| .PD 0 |
| DDIR_READ does fallocate(,mode = FALLOC_FL_KEEP_SIZE,). |
| .P |
| DIR_WRITE does fallocate(,mode = 0). |
| .P |
| DDIR_TRIM does fallocate(,mode = FALLOC_FL_KEEP_SIZE|FALLOC_FL_PUNCH_HOLE). |
| .PD |
| .RE |
| .TP |
| .B ftruncate |
| I/O engine that sends \fBftruncate\fR\|(2) operations in response |
| to write (DDIR_WRITE) events. Each ftruncate issued sets the file's |
| size to the current block offset. \fBblocksize\fR is ignored. |
| .TP |
| .B e4defrag |
| I/O engine that does regular EXT4_IOC_MOVE_EXT ioctls to simulate |
| defragment activity in request to DDIR_WRITE event. |
| .TP |
| .B rados |
| I/O engine supporting direct access to Ceph Reliable Autonomic Distributed |
| Object Store (RADOS) via librados. This ioengine defines engine specific |
| options. |
| .TP |
| .B rbd |
| I/O engine supporting direct access to Ceph Rados Block Devices |
| (RBD) via librbd without the need to use the kernel rbd driver. This |
| ioengine defines engine specific options. |
| .TP |
| .B http |
| I/O engine supporting GET/PUT requests over HTTP(S) with libcurl to |
| a WebDAV or S3 endpoint. This ioengine defines engine specific options. |
| |
| This engine only supports direct IO of iodepth=1; you need to scale this |
| via numjobs. blocksize defines the size of the objects to be created. |
| |
| TRIM is translated to object deletion. |
| .TP |
| .B gfapi |
| Using GlusterFS libgfapi sync interface to direct access to |
| GlusterFS volumes without having to go through FUSE. This ioengine |
| defines engine specific options. |
| .TP |
| .B gfapi_async |
| Using GlusterFS libgfapi async interface to direct access to |
| GlusterFS volumes without having to go through FUSE. This ioengine |
| defines engine specific options. |
| .TP |
| .B libhdfs |
| Read and write through Hadoop (HDFS). The \fBfilename\fR option |
| is used to specify host,port of the hdfs name\-node to connect. This |
| engine interprets offsets a little differently. In HDFS, files once |
| created cannot be modified so random writes are not possible. To |
| imitate this the libhdfs engine expects a bunch of small files to be |
| created over HDFS and will randomly pick a file from them |
| based on the offset generated by fio backend (see the example |
| job file to create such files, use `rw=write' option). Please |
| note, it may be necessary to set environment variables to work |
| with HDFS/libhdfs properly. Each job uses its own connection to |
| HDFS. |
| .TP |
| .B mtd |
| Read, write and erase an MTD character device (e.g., |
| `/dev/mtd0'). Discards are treated as erases. Depending on the |
| underlying device type, the I/O may have to go in a certain pattern, |
| e.g., on NAND, writing sequentially to erase blocks and discarding |
| before overwriting. The \fBtrimwrite\fR mode works well for this |
| constraint. |
| .TP |
| .B pmemblk |
| Read and write using filesystem DAX to a file on a filesystem |
| mounted with DAX on a persistent memory device through the PMDK |
| libpmemblk library. |
| .TP |
| .B dev\-dax |
| Read and write using device DAX to a persistent memory device (e.g., |
| /dev/dax0.0) through the PMDK libpmem library. |
| .TP |
| .B external |
| Prefix to specify loading an external I/O engine object file. Append |
| the engine filename, e.g. `ioengine=external:/tmp/foo.o' to load |
| ioengine `foo.o' in `/tmp'. The path can be either |
| absolute or relative. See `engines/skeleton_external.c' in the fio source for |
| details of writing an external I/O engine. |
| .TP |
| .B filecreate |
| Simply create the files and do no I/O to them. You still need to set |
| \fBfilesize\fR so that all the accounting still occurs, but no actual I/O will be |
| done other than creating the file. |
| .TP |
| .B filestat |
| Simply do stat() and do no I/O to the file. You need to set 'filesize' |
| and 'nrfiles', so that files will be created. |
| This engine is to measure file lookup and meta data access. |
| .TP |
| .B libpmem |
| Read and write using mmap I/O to a file on a filesystem |
| mounted with DAX on a persistent memory device through the PMDK |
| libpmem library. |
| .TP |
| .B ime_psync |
| Synchronous read and write using DDN's Infinite Memory Engine (IME). This |
| engine is very basic and issues calls to IME whenever an IO is queued. |
| .TP |
| .B ime_psyncv |
| Synchronous read and write using DDN's Infinite Memory Engine (IME). This |
| engine uses iovecs and will try to stack as much IOs as possible (if the IOs |
| are "contiguous" and the IO depth is not exceeded) before issuing a call to IME. |
| .TP |
| .B ime_aio |
| Asynchronous read and write using DDN's Infinite Memory Engine (IME). This |
| engine will try to stack as much IOs as possible by creating requests for IME. |
| FIO will then decide when to commit these requests. |
| .TP |
| .B libiscsi |
| Read and write iscsi lun with libiscsi. |
| .TP |
| .B nbd |
| Synchronous read and write a Network Block Device (NBD). |
| .SS "I/O engine specific parameters" |
| In addition, there are some parameters which are only valid when a specific |
| \fBioengine\fR is in use. These are used identically to normal parameters, |
| with the caveat that when used on the command line, they must come after the |
| \fBioengine\fR that defines them is selected. |
| .TP |
| .BI (io_uring, libaio)cmdprio_percentage \fR=\fPint |
| Set the percentage of I/O that will be issued with higher priority by setting |
| the priority bit. Non-read I/O is likely unaffected by ``cmdprio_percentage``. |
| This option cannot be used with the `prio` or `prioclass` options. For this |
| option to set the priority bit properly, NCQ priority must be supported and |
| enabled and `direct=1' option must be used. fio must also be run as the root |
| user. |
| .TP |
| .BI (io_uring)fixedbufs |
| If fio is asked to do direct IO, then Linux will map pages for each IO call, and |
| release them when IO is done. If this option is set, the pages are pre-mapped |
| before IO is started. This eliminates the need to map and release for each IO. |
| This is more efficient, and reduces the IO latency as well. |
| .TP |
| .BI (io_uring)hipri |
| If this option is set, fio will attempt to use polled IO completions. Normal IO |
| completions generate interrupts to signal the completion of IO, polled |
| completions do not. Hence they are require active reaping by the application. |
| The benefits are more efficient IO for high IOPS scenarios, and lower latencies |
| for low queue depth IO. |
| .TP |
| .BI (io_uring)registerfiles |
| With this option, fio registers the set of files being used with the kernel. |
| This avoids the overhead of managing file counts in the kernel, making the |
| submission and completion part more lightweight. Required for the below |
| sqthread_poll option. |
| .TP |
| .BI (io_uring)sqthread_poll |
| Normally fio will submit IO by issuing a system call to notify the kernel of |
| available items in the SQ ring. If this option is set, the act of submitting IO |
| will be done by a polling thread in the kernel. This frees up cycles for fio, at |
| the cost of using more CPU in the system. |
| .TP |
| .BI (io_uring)sqthread_poll_cpu |
| When `sqthread_poll` is set, this option provides a way to define which CPU |
| should be used for the polling thread. |
| .TP |
| .BI (libaio)userspace_reap |
| Normally, with the libaio engine in use, fio will use the |
| \fBio_getevents\fR\|(3) system call to reap newly returned events. With |
| this flag turned on, the AIO ring will be read directly from user-space to |
| reap events. The reaping mode is only enabled when polling for a minimum of |
| 0 events (e.g. when `iodepth_batch_complete=0'). |
| .TP |
| .BI (pvsync2)hipri |
| Set RWF_HIPRI on I/O, indicating to the kernel that it's of higher priority |
| than normal. |
| .TP |
| .BI (pvsync2)hipri_percentage |
| When hipri is set this determines the probability of a pvsync2 I/O being high |
| priority. The default is 100%. |
| .TP |
| .BI (pvsync2,libaio,io_uring)nowait |
| By default if a request cannot be executed immediately (e.g. resource starvation, |
| waiting on locks) it is queued and the initiating process will be blocked until |
| the required resource becomes free. |
| This option sets the RWF_NOWAIT flag (supported from the 4.14 Linux kernel) and |
| the call will return instantly with EAGAIN or a partial result rather than waiting. |
| |
| It is useful to also use \fBignore_error\fR=EAGAIN when using this option. |
| Note: glibc 2.27, 2.28 have a bug in syscall wrappers preadv2, pwritev2. |
| They return EOPNOTSUP instead of EAGAIN. |
| |
| For cached I/O, using this option usually means a request operates only with |
| cached data. Currently the RWF_NOWAIT flag does not supported for cached write. |
| For direct I/O, requests will only succeed if cache invalidation isn't required, |
| file blocks are fully allocated and the disk request could be issued immediately. |
| .TP |
| .BI (cpuio)cpuload \fR=\fPint |
| Attempt to use the specified percentage of CPU cycles. This is a mandatory |
| option when using cpuio I/O engine. |
| .TP |
| .BI (cpuio)cpuchunks \fR=\fPint |
| Split the load into cycles of the given time. In microseconds. |
| .TP |
| .BI (cpuio)exit_on_io_done \fR=\fPbool |
| Detect when I/O threads are done, then exit. |
| .TP |
| .BI (libhdfs)namenode \fR=\fPstr |
| The hostname or IP address of a HDFS cluster namenode to contact. |
| .TP |
| .BI (libhdfs)port |
| The listening port of the HFDS cluster namenode. |
| .TP |
| .BI (netsplice,net)port |
| The TCP or UDP port to bind to or connect to. If this is used with |
| \fBnumjobs\fR to spawn multiple instances of the same job type, then |
| this will be the starting port number since fio will use a range of |
| ports. |
| .TP |
| .BI (rdma)port |
| The port to use for RDMA-CM communication. This should be the same |
| value on the client and the server side. |
| .TP |
| .BI (netsplice,net, rdma)hostname \fR=\fPstr |
| The hostname or IP address to use for TCP, UDP or RDMA-CM based I/O. |
| If the job is a TCP listener or UDP reader, the hostname is not used |
| and must be omitted unless it is a valid UDP multicast address. |
| .TP |
| .BI (netsplice,net)interface \fR=\fPstr |
| The IP address of the network interface used to send or receive UDP |
| multicast. |
| .TP |
| .BI (netsplice,net)ttl \fR=\fPint |
| Time\-to\-live value for outgoing UDP multicast packets. Default: 1. |
| .TP |
| .BI (netsplice,net)nodelay \fR=\fPbool |
| Set TCP_NODELAY on TCP connections. |
| .TP |
| .BI (netsplice,net)protocol \fR=\fPstr "\fR,\fP proto" \fR=\fPstr |
| The network protocol to use. Accepted values are: |
| .RS |
| .RS |
| .TP |
| .B tcp |
| Transmission control protocol. |
| .TP |
| .B tcpv6 |
| Transmission control protocol V6. |
| .TP |
| .B udp |
| User datagram protocol. |
| .TP |
| .B udpv6 |
| User datagram protocol V6. |
| .TP |
| .B unix |
| UNIX domain socket. |
| .RE |
| .P |
| When the protocol is TCP or UDP, the port must also be given, as well as the |
| hostname if the job is a TCP listener or UDP reader. For unix sockets, the |
| normal \fBfilename\fR option should be used and the port is invalid. |
| .RE |
| .TP |
| .BI (netsplice,net)listen |
| For TCP network connections, tell fio to listen for incoming connections |
| rather than initiating an outgoing connection. The \fBhostname\fR must |
| be omitted if this option is used. |
| .TP |
| .BI (netsplice,net)pingpong |
| Normally a network writer will just continue writing data, and a network |
| reader will just consume packages. If `pingpong=1' is set, a writer will |
| send its normal payload to the reader, then wait for the reader to send the |
| same payload back. This allows fio to measure network latencies. The |
| submission and completion latencies then measure local time spent sending or |
| receiving, and the completion latency measures how long it took for the |
| other end to receive and send back. For UDP multicast traffic |
| `pingpong=1' should only be set for a single reader when multiple readers |
| are listening to the same address. |
| .TP |
| .BI (netsplice,net)window_size \fR=\fPint |
| Set the desired socket buffer size for the connection. |
| .TP |
| .BI (netsplice,net)mss \fR=\fPint |
| Set the TCP maximum segment size (TCP_MAXSEG). |
| .TP |
| .BI (e4defrag)donorname \fR=\fPstr |
| File will be used as a block donor (swap extents between files). |
| .TP |
| .BI (e4defrag)inplace \fR=\fPint |
| Configure donor file blocks allocation strategy: |
| .RS |
| .RS |
| .TP |
| .B 0 |
| Default. Preallocate donor's file on init. |
| .TP |
| .B 1 |
| Allocate space immediately inside defragment event, and free right |
| after event. |
| .RE |
| .RE |
| .TP |
| .BI (rbd,rados)clustername \fR=\fPstr |
| Specifies the name of the Ceph cluster. |
| .TP |
| .BI (rbd)rbdname \fR=\fPstr |
| Specifies the name of the RBD. |
| .TP |
| .BI (rbd,rados)pool \fR=\fPstr |
| Specifies the name of the Ceph pool containing RBD or RADOS data. |
| .TP |
| .BI (rbd,rados)clientname \fR=\fPstr |
| Specifies the username (without the 'client.' prefix) used to access the |
| Ceph cluster. If the \fBclustername\fR is specified, the \fBclientname\fR shall be |
| the full *type.id* string. If no type. prefix is given, fio will add 'client.' |
| by default. |
| .TP |
| .BI (rbd,rados)busy_poll \fR=\fPbool |
| Poll store instead of waiting for completion. Usually this provides better |
| throughput at cost of higher(up to 100%) CPU utilization. |
| .TP |
| .BI (http)http_host \fR=\fPstr |
| Hostname to connect to. For S3, this could be the bucket name. Default |
| is \fBlocalhost\fR |
| .TP |
| .BI (http)http_user \fR=\fPstr |
| Username for HTTP authentication. |
| .TP |
| .BI (http)http_pass \fR=\fPstr |
| Password for HTTP authentication. |
| .TP |
| .BI (http)https \fR=\fPstr |
| Whether to use HTTPS instead of plain HTTP. \fRon\fP enables HTTPS; |
| \fRinsecure\fP will enable HTTPS, but disable SSL peer verification (use |
| with caution!). Default is \fBoff\fR. |
| .TP |
| .BI (http)http_mode \fR=\fPstr |
| Which HTTP access mode to use: webdav, swift, or s3. Default is |
| \fBwebdav\fR. |
| .TP |
| .BI (http)http_s3_region \fR=\fPstr |
| The S3 region/zone to include in the request. Default is \fBus-east-1\fR. |
| .TP |
| .BI (http)http_s3_key \fR=\fPstr |
| The S3 secret key. |
| .TP |
| .BI (http)http_s3_keyid \fR=\fPstr |
| The S3 key/access id. |
| .TP |
| .BI (http)http_swift_auth_token \fR=\fPstr |
| The Swift auth token. See the example configuration file on how to |
| retrieve this. |
| .TP |
| .BI (http)http_verbose \fR=\fPint |
| Enable verbose requests from libcurl. Useful for debugging. 1 turns on |
| verbose logging from libcurl, 2 additionally enables HTTP IO tracing. |
| Default is \fB0\fR |
| .TP |
| .BI (mtd)skip_bad \fR=\fPbool |
| Skip operations against known bad blocks. |
| .TP |
| .BI (libhdfs)hdfsdirectory |
| libhdfs will create chunk in this HDFS directory. |
| .TP |
| .BI (libhdfs)chunk_size |
| The size of the chunk to use for each file. |
| .TP |
| .BI (rdma)verb \fR=\fPstr |
| The RDMA verb to use on this side of the RDMA ioengine |
| connection. Valid values are write, read, send and recv. These |
| correspond to the equivalent RDMA verbs (e.g. write = rdma_write |
| etc.). Note that this only needs to be specified on the client side of |
| the connection. See the examples folder. |
| .TP |
| .BI (rdma)bindname \fR=\fPstr |
| The name to use to bind the local RDMA-CM connection to a local RDMA |
| device. This could be a hostname or an IPv4 or IPv6 address. On the |
| server side this will be passed into the rdma_bind_addr() function and |
| on the client site it will be used in the rdma_resolve_add() |
| function. This can be useful when multiple paths exist between the |
| client and the server or in certain loopback configurations. |
| .TP |
| .BI (filestat)stat_type \fR=\fPstr |
| Specify stat system call type to measure lookup/getattr performance. |
| Default is \fBstat\fR for \fBstat\fR\|(2). |
| .TP |
| .BI (sg)readfua \fR=\fPbool |
| With readfua option set to 1, read operations include the force |
| unit access (fua) flag. Default: 0. |
| .TP |
| .BI (sg)writefua \fR=\fPbool |
| With writefua option set to 1, write operations include the force |
| unit access (fua) flag. Default: 0. |
| .TP |
| .BI (sg)sg_write_mode \fR=\fPstr |
| Specify the type of write commands to issue. This option can take three |
| values: |
| .RS |
| .RS |
| .TP |
| .B write (default) |
| Write opcodes are issued as usual |
| .TP |
| .B verify |
| Issue WRITE AND VERIFY commands. The BYTCHK bit is set to 0. This |
| directs the device to carry out a medium verification with no data |
| comparison. The writefua option is ignored with this selection. |
| .TP |
| .B same |
| Issue WRITE SAME commands. This transfers a single block to the device |
| and writes this same block of data to a contiguous sequence of LBAs |
| beginning at the specified offset. fio's block size parameter |
| specifies the amount of data written with each command. However, the |
| amount of data actually transferred to the device is equal to the |
| device's block (sector) size. For a device with 512 byte sectors, |
| blocksize=8k will write 16 sectors with each command. fio will still |
| generate 8k of data for each command butonly the first 512 bytes will |
| be used and transferred to the device. The writefua option is ignored |
| with this selection. |
| .RE |
| .RE |
| .TP |
| .BI (nbd)uri \fR=\fPstr |
| Specify the NBD URI of the server to test. |
| The string is a standard NBD URI (see |
| \fIhttps://github.com/NetworkBlockDevice/nbd/tree/master/doc\fR). |
| Example URIs: |
| .RS |
| .RS |
| .TP |
| \fInbd://localhost:10809\fR |
| .TP |
| \fInbd+unix:///?socket=/tmp/socket\fR |
| .TP |
| \fInbds://tlshost/exportname\fR |
| |
| .SS "I/O depth" |
| .TP |
| .BI iodepth \fR=\fPint |
| Number of I/O units to keep in flight against the file. Note that |
| increasing \fBiodepth\fR beyond 1 will not affect synchronous ioengines (except |
| for small degrees when \fBverify_async\fR is in use). Even async |
| engines may impose OS restrictions causing the desired depth not to be |
| achieved. This may happen on Linux when using libaio and not setting |
| `direct=1', since buffered I/O is not async on that OS. Keep an |
| eye on the I/O depth distribution in the fio output to verify that the |
| achieved depth is as expected. Default: 1. |
| .TP |
| .BI iodepth_batch_submit \fR=\fPint "\fR,\fP iodepth_batch" \fR=\fPint |
| This defines how many pieces of I/O to submit at once. It defaults to 1 |
| which means that we submit each I/O as soon as it is available, but can be |
| raised to submit bigger batches of I/O at the time. If it is set to 0 the |
| \fBiodepth\fR value will be used. |
| .TP |
| .BI iodepth_batch_complete_min \fR=\fPint "\fR,\fP iodepth_batch_complete" \fR=\fPint |
| This defines how many pieces of I/O to retrieve at once. It defaults to 1 |
| which means that we'll ask for a minimum of 1 I/O in the retrieval process |
| from the kernel. The I/O retrieval will go on until we hit the limit set by |
| \fBiodepth_low\fR. If this variable is set to 0, then fio will always |
| check for completed events before queuing more I/O. This helps reduce I/O |
| latency, at the cost of more retrieval system calls. |
| .TP |
| .BI iodepth_batch_complete_max \fR=\fPint |
| This defines maximum pieces of I/O to retrieve at once. This variable should |
| be used along with \fBiodepth_batch_complete_min\fR=\fIint\fR variable, |
| specifying the range of min and max amount of I/O which should be |
| retrieved. By default it is equal to \fBiodepth_batch_complete_min\fR |
| value. Example #1: |
| .RS |
| .RS |
| .P |
| .PD 0 |
| iodepth_batch_complete_min=1 |
| .P |
| iodepth_batch_complete_max=<iodepth> |
| .PD |
| .RE |
| .P |
| which means that we will retrieve at least 1 I/O and up to the whole |
| submitted queue depth. If none of I/O has been completed yet, we will wait. |
| Example #2: |
| .RS |
| .P |
| .PD 0 |
| iodepth_batch_complete_min=0 |
| .P |
| iodepth_batch_complete_max=<iodepth> |
| .PD |
| .RE |
| .P |
| which means that we can retrieve up to the whole submitted queue depth, but |
| if none of I/O has been completed yet, we will NOT wait and immediately exit |
| the system call. In this example we simply do polling. |
| .RE |
| .TP |
| .BI iodepth_low \fR=\fPint |
| The low water mark indicating when to start filling the queue |
| again. Defaults to the same as \fBiodepth\fR, meaning that fio will |
| attempt to keep the queue full at all times. If \fBiodepth\fR is set to |
| e.g. 16 and \fBiodepth_low\fR is set to 4, then after fio has filled the queue of |
| 16 requests, it will let the depth drain down to 4 before starting to fill |
| it again. |
| .TP |
| .BI serialize_overlap \fR=\fPbool |
| Serialize in-flight I/Os that might otherwise cause or suffer from data races. |
| When two or more I/Os are submitted simultaneously, there is no guarantee that |
| the I/Os will be processed or completed in the submitted order. Further, if |
| two or more of those I/Os are writes, any overlapping region between them can |
| become indeterminate/undefined on certain storage. These issues can cause |
| verification to fail erratically when at least one of the racing I/Os is |
| changing data and the overlapping region has a non-zero size. Setting |
| \fBserialize_overlap\fR tells fio to avoid provoking this behavior by explicitly |
| serializing in-flight I/Os that have a non-zero overlap. Note that setting |
| this option can reduce both performance and the \fBiodepth\fR achieved. |
| .RS |
| .P |
| This option only applies to I/Os issued for a single job except when it is |
| enabled along with \fBio_submit_mode\fR=offload. In offload mode, fio |
| will check for overlap among all I/Os submitted by offload jobs with \fBserialize_overlap\fR |
| enabled. |
| .P |
| Default: false. |
| .RE |
| .TP |
| .BI io_submit_mode \fR=\fPstr |
| This option controls how fio submits the I/O to the I/O engine. The default |
| is `inline', which means that the fio job threads submit and reap I/O |
| directly. If set to `offload', the job threads will offload I/O submission |
| to a dedicated pool of I/O threads. This requires some coordination and thus |
| has a bit of extra overhead, especially for lower queue depth I/O where it |
| can increase latencies. The benefit is that fio can manage submission rates |
| independently of the device completion rates. This avoids skewed latency |
| reporting if I/O gets backed up on the device side (the coordinated omission |
| problem). Note that this option cannot reliably be used with async IO engines. |
| .SS "I/O rate" |
| .TP |
| .BI thinktime \fR=\fPtime |
| Stall the job for the specified period of time after an I/O has completed before issuing the |
| next. May be used to simulate processing being done by an application. |
| When the unit is omitted, the value is interpreted in microseconds. See |
| \fBthinktime_blocks\fR and \fBthinktime_spin\fR. |
| .TP |
| .BI thinktime_spin \fR=\fPtime |
| Only valid if \fBthinktime\fR is set - pretend to spend CPU time doing |
| something with the data received, before falling back to sleeping for the |
| rest of the period specified by \fBthinktime\fR. When the unit is |
| omitted, the value is interpreted in microseconds. |
| .TP |
| .BI thinktime_blocks \fR=\fPint |
| Only valid if \fBthinktime\fR is set - control how many blocks to issue, |
| before waiting \fBthinktime\fR usecs. If not set, defaults to 1 which will make |
| fio wait \fBthinktime\fR usecs after every block. This effectively makes any |
| queue depth setting redundant, since no more than 1 I/O will be queued |
| before we have to complete it and do our \fBthinktime\fR. In other words, this |
| setting effectively caps the queue depth if the latter is larger. |
| .TP |
| .BI rate \fR=\fPint[,int][,int] |
| Cap the bandwidth used by this job. The number is in bytes/sec, the normal |
| suffix rules apply. Comma-separated values may be specified for reads, |
| writes, and trims as described in \fBblocksize\fR. |
| .RS |
| .P |
| For example, using `rate=1m,500k' would limit reads to 1MiB/sec and writes to |
| 500KiB/sec. Capping only reads or writes can be done with `rate=,500k' or |
| `rate=500k,' where the former will only limit writes (to 500KiB/sec) and the |
| latter will only limit reads. |
| .RE |
| .TP |
| .BI rate_min \fR=\fPint[,int][,int] |
| Tell fio to do whatever it can to maintain at least this bandwidth. Failing |
| to meet this requirement will cause the job to exit. Comma-separated values |
| may be specified for reads, writes, and trims as described in |
| \fBblocksize\fR. |
| .TP |
| .BI rate_iops \fR=\fPint[,int][,int] |
| Cap the bandwidth to this number of IOPS. Basically the same as |
| \fBrate\fR, just specified independently of bandwidth. If the job is |
| given a block size range instead of a fixed value, the smallest block size |
| is used as the metric. Comma-separated values may be specified for reads, |
| writes, and trims as described in \fBblocksize\fR. |
| .TP |
| .BI rate_iops_min \fR=\fPint[,int][,int] |
| If fio doesn't meet this rate of I/O, it will cause the job to exit. |
| Comma-separated values may be specified for reads, writes, and trims as |
| described in \fBblocksize\fR. |
| .TP |
| .BI rate_process \fR=\fPstr |
| This option controls how fio manages rated I/O submissions. The default is |
| `linear', which submits I/O in a linear fashion with fixed delays between |
| I/Os that gets adjusted based on I/O completion rates. If this is set to |
| `poisson', fio will submit I/O based on a more real world random request |
| flow, known as the Poisson process |
| (\fIhttps://en.wikipedia.org/wiki/Poisson_point_process\fR). The lambda will be |
| 10^6 / IOPS for the given workload. |
| .TP |
| .BI rate_ignore_thinktime \fR=\fPbool |
| By default, fio will attempt to catch up to the specified rate setting, if any |
| kind of thinktime setting was used. If this option is set, then fio will |
| ignore the thinktime and continue doing IO at the specified rate, instead of |
| entering a catch-up mode after thinktime is done. |
| .SS "I/O latency" |
| .TP |
| .BI latency_target \fR=\fPtime |
| If set, fio will attempt to find the max performance point that the given |
| workload will run at while maintaining a latency below this target. When |
| the unit is omitted, the value is interpreted in microseconds. See |
| \fBlatency_window\fR and \fBlatency_percentile\fR. |
| .TP |
| .BI latency_window \fR=\fPtime |
| Used with \fBlatency_target\fR to specify the sample window that the job |
| is run at varying queue depths to test the performance. When the unit is |
| omitted, the value is interpreted in microseconds. |
| .TP |
| .BI latency_percentile \fR=\fPfloat |
| The percentage of I/Os that must fall within the criteria specified by |
| \fBlatency_target\fR and \fBlatency_window\fR. If not set, this |
| defaults to 100.0, meaning that all I/Os must be equal or below to the value |
| set by \fBlatency_target\fR. |
| .TP |
| .BI latency_run \fR=\fPbool |
| Used with \fBlatency_target\fR. If false (default), fio will find the highest |
| queue depth that meets \fBlatency_target\fR and exit. If true, fio will continue |
| running and try to meet \fBlatency_target\fR by adjusting queue depth. |
| .TP |
| .BI max_latency \fR=\fPtime |
| If set, fio will exit the job with an ETIMEDOUT error if it exceeds this |
| maximum latency. When the unit is omitted, the value is interpreted in |
| microseconds. |
| .TP |
| .BI rate_cycle \fR=\fPint |
| Average bandwidth for \fBrate\fR and \fBrate_min\fR over this number |
| of milliseconds. Defaults to 1000. |
| .SS "I/O replay" |
| .TP |
| .BI write_iolog \fR=\fPstr |
| Write the issued I/O patterns to the specified file. See |
| \fBread_iolog\fR. Specify a separate file for each job, otherwise the |
| iologs will be interspersed and the file may be corrupt. |
| .TP |
| .BI read_iolog \fR=\fPstr |
| Open an iolog with the specified filename and replay the I/O patterns it |
| contains. This can be used to store a workload and replay it sometime |
| later. The iolog given may also be a blktrace binary file, which allows fio |
| to replay a workload captured by blktrace. See |
| \fBblktrace\fR\|(8) for how to capture such logging data. For blktrace |
| replay, the file needs to be turned into a blkparse binary data file first |
| (`blkparse <device> \-o /dev/null \-d file_for_fio.bin'). |
| You can specify a number of files by separating the names with a ':' character. |
| See the \fBfilename\fR option for information on how to escape ':' |
| characters within the file names. These files will be sequentially assigned to |
| job clones created by \fBnumjobs\fR. '-' is a reserved name, meaning read from |
| stdin, notably if \fBfilename\fR is set to '-' which means stdin as well, |
| then this flag can't be set to '-'. |
| .TP |
| .BI read_iolog_chunked \fR=\fPbool |
| Determines how iolog is read. If false (default) entire \fBread_iolog\fR will |
| be read at once. If selected true, input from iolog will be read gradually. |
| Useful when iolog is very large, or it is generated. |
| .TP |
| .BI merge_blktrace_file \fR=\fPstr |
| When specified, rather than replaying the logs passed to \fBread_iolog\fR, |
| the logs go through a merge phase which aggregates them into a single blktrace. |
| The resulting file is then passed on as the \fBread_iolog\fR parameter. The |
| intention here is to make the order of events consistent. This limits the |
| influence of the scheduler compared to replaying multiple blktraces via |
| concurrent jobs. |
| .TP |
| .BI merge_blktrace_scalars \fR=\fPfloat_list |
| This is a percentage based option that is index paired with the list of files |
| passed to \fBread_iolog\fR. When merging is performed, scale the time of each |
| event by the corresponding amount. For example, |
| `\-\-merge_blktrace_scalars="50:100"' runs the first trace in halftime and the |
| second trace in realtime. This knob is separately tunable from |
| \fBreplay_time_scale\fR which scales the trace during runtime and will not |
| change the output of the merge unlike this option. |
| .TP |
| .BI merge_blktrace_iters \fR=\fPfloat_list |
| This is a whole number option that is index paired with the list of files |
| passed to \fBread_iolog\fR. When merging is performed, run each trace for |
| the specified number of iterations. For example, |
| `\-\-merge_blktrace_iters="2:1"' runs the first trace for two iterations |
| and the second trace for one iteration. |
| .TP |
| .BI replay_no_stall \fR=\fPbool |
| When replaying I/O with \fBread_iolog\fR the default behavior is to |
| attempt to respect the timestamps within the log and replay them with the |
| appropriate delay between IOPS. By setting this variable fio will not |
| respect the timestamps and attempt to replay them as fast as possible while |
| still respecting ordering. The result is the same I/O pattern to a given |
| device, but different timings. |
| .TP |
| .BI replay_time_scale \fR=\fPint |
| When replaying I/O with \fBread_iolog\fR, fio will honor the original timing |
| in the trace. With this option, it's possible to scale the time. It's a |
| percentage option, if set to 50 it means run at 50% the original IO rate in |
| the trace. If set to 200, run at twice the original IO rate. Defaults to 100. |
| .TP |
| .BI replay_redirect \fR=\fPstr |
| While replaying I/O patterns using \fBread_iolog\fR the default behavior |
| is to replay the IOPS onto the major/minor device that each IOP was recorded |
| from. This is sometimes undesirable because on a different machine those |
| major/minor numbers can map to a different device. Changing hardware on the |
| same system can also result in a different major/minor mapping. |
| \fBreplay_redirect\fR causes all I/Os to be replayed onto the single specified |
| device regardless of the device it was recorded |
| from. i.e. `replay_redirect=/dev/sdc' would cause all I/O |
| in the blktrace or iolog to be replayed onto `/dev/sdc'. This means |
| multiple devices will be replayed onto a single device, if the trace |
| contains multiple devices. If you want multiple devices to be replayed |
| concurrently to multiple redirected devices you must blkparse your trace |
| into separate traces and replay them with independent fio invocations. |
| Unfortunately this also breaks the strict time ordering between multiple |
| device accesses. |
| .TP |
| .BI replay_align \fR=\fPint |
| Force alignment of the byte offsets in a trace to this value. The value |
| must be a power of 2. |
| .TP |
| .BI replay_scale \fR=\fPint |
| Scale bye offsets down by this factor when replaying traces. Should most |
| likely use \fBreplay_align\fR as well. |
| .SS "Threads, processes and job synchronization" |
| .TP |
| .BI replay_skip \fR=\fPstr |
| Sometimes it's useful to skip certain IO types in a replay trace. This could |
| be, for instance, eliminating the writes in the trace. Or not replaying the |
| trims/discards, if you are redirecting to a device that doesn't support them. |
| This option takes a comma separated list of read, write, trim, sync. |
| .TP |
| .BI thread |
| Fio defaults to creating jobs by using fork, however if this option is |
| given, fio will create jobs by using POSIX Threads' function |
| \fBpthread_create\fR\|(3) to create threads instead. |
| .TP |
| .BI wait_for \fR=\fPstr |
| If set, the current job won't be started until all workers of the specified |
| waitee job are done. |
| .\" ignore blank line here from HOWTO as it looks normal without it |
| \fBwait_for\fR operates on the job name basis, so there are a few |
| limitations. First, the waitee must be defined prior to the waiter job |
| (meaning no forward references). Second, if a job is being referenced as a |
| waitee, it must have a unique name (no duplicate waitees). |
| .TP |
| .BI nice \fR=\fPint |
| Run the job with the given nice value. See man \fBnice\fR\|(2). |
| .\" ignore blank line here from HOWTO as it looks normal without it |
| On Windows, values less than \-15 set the process class to "High"; \-1 through |
| \-15 set "Above Normal"; 1 through 15 "Below Normal"; and above 15 "Idle" |
| priority class. |
| .TP |
| .BI prio \fR=\fPint |
| Set the I/O priority value of this job. Linux limits us to a positive value |
| between 0 and 7, with 0 being the highest. See man |
| \fBionice\fR\|(1). Refer to an appropriate manpage for other operating |
| systems since meaning of priority may differ. For per-command priority |
| setting, see I/O engine specific `cmdprio_percentage` and `hipri_percentage` |
| options. |
| .TP |
| .BI prioclass \fR=\fPint |
| Set the I/O priority class. See man \fBionice\fR\|(1). For per-command |
| priority setting, see I/O engine specific `cmdprio_percentage` and `hipri_percent` |
| options. |
| .TP |
| .BI cpus_allowed \fR=\fPstr |
| Controls the same options as \fBcpumask\fR, but accepts a textual |
| specification of the permitted CPUs instead and CPUs are indexed from 0. So |
| to use CPUs 0 and 5 you would specify `cpus_allowed=0,5'. This option also |
| allows a range of CPUs to be specified \-\- say you wanted a binding to CPUs |
| 0, 5, and 8 to 15, you would set `cpus_allowed=0,5,8\-15'. |
| .RS |
| .P |
| On Windows, when `cpus_allowed' is unset only CPUs from fio's current |
| processor group will be used and affinity settings are inherited from the |
| system. An fio build configured to target Windows 7 makes options that set |
| CPUs processor group aware and values will set both the processor group |
| and a CPU from within that group. For example, on a system where processor |
| group 0 has 40 CPUs and processor group 1 has 32 CPUs, `cpus_allowed' |
| values between 0 and 39 will bind CPUs from processor group 0 and |
| `cpus_allowed' values between 40 and 71 will bind CPUs from processor |
| group 1. When using `cpus_allowed_policy=shared' all CPUs specified by a |
| single `cpus_allowed' option must be from the same processor group. For |
| Windows fio builds not built for Windows 7, CPUs will only be selected from |
| (and be relative to) whatever processor group fio happens to be running in |
| and CPUs from other processor groups cannot be used. |
| .RE |
| .TP |
| .BI cpus_allowed_policy \fR=\fPstr |
| Set the policy of how fio distributes the CPUs specified by |
| \fBcpus_allowed\fR or \fBcpumask\fR. Two policies are supported: |
| .RS |
| .RS |
| .TP |
| .B shared |
| All jobs will share the CPU set specified. |
| .TP |
| .B split |
| Each job will get a unique CPU from the CPU set. |
| .RE |
| .P |
| \fBshared\fR is the default behavior, if the option isn't specified. If |
| \fBsplit\fR is specified, then fio will assign one cpu per job. If not |
| enough CPUs are given for the jobs listed, then fio will roundrobin the CPUs |
| in the set. |
| .RE |
| .TP |
| .BI cpumask \fR=\fPint |
| Set the CPU affinity of this job. The parameter given is a bit mask of |
| allowed CPUs the job may run on. So if you want the allowed CPUs to be 1 |
| and 5, you would pass the decimal value of (1 << 1 | 1 << 5), or 34. See man |
| \fBsched_setaffinity\fR\|(2). This may not work on all supported |
| operating systems or kernel versions. This option doesn't work well for a |
| higher CPU count than what you can store in an integer mask, so it can only |
| control cpus 1\-32. For boxes with larger CPU counts, use |
| \fBcpus_allowed\fR. |
| .TP |
| .BI numa_cpu_nodes \fR=\fPstr |
| Set this job running on specified NUMA nodes' CPUs. The arguments allow |
| comma delimited list of cpu numbers, A\-B ranges, or `all'. Note, to enable |
| NUMA options support, fio must be built on a system with libnuma\-dev(el) |
| installed. |
| .TP |
| .BI numa_mem_policy \fR=\fPstr |
| Set this job's memory policy and corresponding NUMA nodes. Format of the |
| arguments: |
| .RS |
| .RS |
| .P |
| <mode>[:<nodelist>] |
| .RE |
| .P |
| `mode' is one of the following memory policies: `default', `prefer', |
| `bind', `interleave' or `local'. For `default' and `local' memory |
| policies, no node needs to be specified. For `prefer', only one node is |
| allowed. For `bind' and `interleave' the `nodelist' may be as |
| follows: a comma delimited list of numbers, A\-B ranges, or `all'. |
| .RE |
| .TP |
| .BI cgroup \fR=\fPstr |
| Add job to this control group. If it doesn't exist, it will be created. The |
| system must have a mounted cgroup blkio mount point for this to work. If |
| your system doesn't have it mounted, you can do so with: |
| .RS |
| .RS |
| .P |
| # mount \-t cgroup \-o blkio none /cgroup |
| .RE |
| .RE |
| .TP |
| .BI cgroup_weight \fR=\fPint |
| Set the weight of the cgroup to this value. See the documentation that comes |
| with the kernel, allowed values are in the range of 100..1000. |
| .TP |
| .BI cgroup_nodelete \fR=\fPbool |
| Normally fio will delete the cgroups it has created after the job |
| completion. To override this behavior and to leave cgroups around after the |
| job completion, set `cgroup_nodelete=1'. This can be useful if one wants |
| to inspect various cgroup files after job completion. Default: false. |
| .TP |
| .BI flow_id \fR=\fPint |
| The ID of the flow. If not specified, it defaults to being a global |
| flow. See \fBflow\fR. |
| .TP |
| .BI flow \fR=\fPint |
| Weight in token-based flow control. If this value is used, |
| then fio regulates the activity between two or more jobs |
| sharing the same flow_id. |
| Fio attempts to keep each job activity proportional to other jobs' activities |
| in the same flow_id group, with respect to requested weight per job. |
| That is, if one job has `flow=3', another job has `flow=2' |
| and another with `flow=1`, then there will be a roughly 3:2:1 ratio |
| in how much one runs vs the others. |
| .TP |
| .BI flow_sleep \fR=\fPint |
| The period of time, in microseconds, to wait after the flow counter |
| has exceeded its proportion before retrying operations. |
| .TP |
| .BI stonewall "\fR,\fB wait_for_previous" |
| Wait for preceding jobs in the job file to exit, before starting this |
| one. Can be used to insert serialization points in the job file. A stone |
| wall also implies starting a new reporting group, see |
| \fBgroup_reporting\fR. Optionally you can use `stonewall=0` to disable or |
| `stonewall=1` to enable it. |
| .TP |
| .BI exitall |
| By default, fio will continue running all other jobs when one job finishes. |
| Sometimes this is not the desired action. Setting \fBexitall\fR will instead |
| make fio terminate all jobs in the same group, as soon as one job of that |
| group finishes. |
| .TP |
| .BI exit_what \fR=\fPstr |
| By default, fio will continue running all other jobs when one job finishes. |
| Sometimes this is not the desired action. Setting \fBexitall\fR will instead |
| make fio terminate all jobs in the same group. The option \fBexit_what\fR |
| allows you to control which jobs get terminated when \fBexitall\fR is enabled. |
| The default value is \fBgroup\fR. |
| The allowed values are: |
| .RS |
| .RS |
| .TP |
| .B all |
| terminates all jobs. |
| .TP |
| .B group |
| is the default and does not change the behaviour of \fBexitall\fR. |
| .TP |
| .B stonewall |
| terminates all currently running jobs across all groups and continues |
| execution with the next stonewalled group. |
| .RE |
| .RE |
| .TP |
| .BI exec_prerun \fR=\fPstr |
| Before running this job, issue the command specified through |
| \fBsystem\fR\|(3). Output is redirected in a file called `jobname.prerun.txt'. |
| .TP |
| .BI exec_postrun \fR=\fPstr |
| After the job completes, issue the command specified though |
| \fBsystem\fR\|(3). Output is redirected in a file called `jobname.postrun.txt'. |
| .TP |
| .BI uid \fR=\fPint |
| Instead of running as the invoking user, set the user ID to this value |
| before the thread/process does any work. |
| .TP |
| .BI gid \fR=\fPint |
| Set group ID, see \fBuid\fR. |
| .SS "Verification" |
| .TP |
| .BI verify_only |
| Do not perform specified workload, only verify data still matches previous |
| invocation of this workload. This option allows one to check data multiple |
| times at a later date without overwriting it. This option makes sense only |
| for workloads that write data, and does not support workloads with the |
| \fBtime_based\fR option set. |
| .TP |
| .BI do_verify \fR=\fPbool |
| Run the verify phase after a write phase. Only valid if \fBverify\fR is |
| set. Default: true. |
| .TP |
| .BI verify \fR=\fPstr |
| If writing to a file, fio can verify the file contents after each iteration |
| of the job. Each verification method also implies verification of special |
| header, which is written to the beginning of each block. This header also |
| includes meta information, like offset of the block, block number, timestamp |
| when block was written, etc. \fBverify\fR can be combined with |
| \fBverify_pattern\fR option. The allowed values are: |
| .RS |
| .RS |
| .TP |
| .B md5 |
| Use an md5 sum of the data area and store it in the header of |
| each block. |
| .TP |
| .B crc64 |
| Use an experimental crc64 sum of the data area and store it in the |
| header of each block. |
| .TP |
| .B crc32c |
| Use a crc32c sum of the data area and store it in the header of |
| each block. This will automatically use hardware acceleration |
| (e.g. SSE4.2 on an x86 or CRC crypto extensions on ARM64) but will |
| fall back to software crc32c if none is found. Generally the |
| fastest checksum fio supports when hardware accelerated. |
| .TP |
| .B crc32c\-intel |
| Synonym for crc32c. |
| .TP |
| .B crc32 |
| Use a crc32 sum of the data area and store it in the header of each |
| block. |
| .TP |
| .B crc16 |
| Use a crc16 sum of the data area and store it in the header of each |
| block. |
| .TP |
| .B crc7 |
| Use a crc7 sum of the data area and store it in the header of each |
| block. |
| .TP |
| .B xxhash |
| Use xxhash as the checksum function. Generally the fastest software |
| checksum that fio supports. |
| .TP |
| .B sha512 |
| Use sha512 as the checksum function. |
| .TP |
| .B sha256 |
| Use sha256 as the checksum function. |
| .TP |
| .B sha1 |
| Use optimized sha1 as the checksum function. |
| .TP |
| .B sha3\-224 |
| Use optimized sha3\-224 as the checksum function. |
| .TP |
| .B sha3\-256 |
| Use optimized sha3\-256 as the checksum function. |
| .TP |
| .B sha3\-384 |
| Use optimized sha3\-384 as the checksum function. |
| .TP |
| .B sha3\-512 |
| Use optimized sha3\-512 as the checksum function. |
| .TP |
| .B meta |
| This option is deprecated, since now meta information is included in |
| generic verification header and meta verification happens by |
| default. For detailed information see the description of the |
| \fBverify\fR setting. This option is kept because of |
| compatibility's sake with old configurations. Do not use it. |
| .TP |
| .B pattern |
| Verify a strict pattern. Normally fio includes a header with some |
| basic information and checksumming, but if this option is set, only |
| the specific pattern set with \fBverify_pattern\fR is verified. |
| .TP |
| .B null |
| Only pretend to verify. Useful for testing internals with |
| `ioengine=null', not for much else. |
| .RE |
| .P |
| This option can be used for repeated burn\-in tests of a system to make sure |
| that the written data is also correctly read back. If the data direction |
| given is a read or random read, fio will assume that it should verify a |
| previously written file. If the data direction includes any form of write, |
| the verify will be of the newly written data. |
| .P |
| To avoid false verification errors, do not use the norandommap option when |
| verifying data with async I/O engines and I/O depths > 1. Or use the |
| norandommap and the lfsr random generator together to avoid writing to the |
| same offset with muliple outstanding I/Os. |
| .RE |
| .TP |
| .BI verify_offset \fR=\fPint |
| Swap the verification header with data somewhere else in the block before |
| writing. It is swapped back before verifying. |
| .TP |
| .BI verify_interval \fR=\fPint |
| Write the verification header at a finer granularity than the |
| \fBblocksize\fR. It will be written for chunks the size of |
| \fBverify_interval\fR. \fBblocksize\fR should divide this evenly. |
| .TP |
| .BI verify_pattern \fR=\fPstr |
| If set, fio will fill the I/O buffers with this pattern. Fio defaults to |
| filling with totally random bytes, but sometimes it's interesting to fill |
| with a known pattern for I/O verification purposes. Depending on the width |
| of the pattern, fio will fill 1/2/3/4 bytes of the buffer at the time (it can |
| be either a decimal or a hex number). The \fBverify_pattern\fR if larger than |
| a 32\-bit quantity has to be a hex number that starts with either "0x" or |
| "0X". Use with \fBverify\fR. Also, \fBverify_pattern\fR supports %o |
| format, which means that for each block offset will be written and then |
| verified back, e.g.: |
| .RS |
| .RS |
| .P |
| verify_pattern=%o |
| .RE |
| .P |
| Or use combination of everything: |
| .RS |
| .P |
| verify_pattern=0xff%o"abcd"\-12 |
| .RE |
| .RE |
| .TP |
| .BI verify_fatal \fR=\fPbool |
| Normally fio will keep checking the entire contents before quitting on a |
| block verification failure. If this option is set, fio will exit the job on |
| the first observed failure. Default: false. |
| .TP |
| .BI verify_dump \fR=\fPbool |
| If set, dump the contents of both the original data block and the data block |
| we read off disk to files. This allows later analysis to inspect just what |
| kind of data corruption occurred. Off by default. |
| .TP |
| .BI verify_async \fR=\fPint |
| Fio will normally verify I/O inline from the submitting thread. This option |
| takes an integer describing how many async offload threads to create for I/O |
| verification instead, causing fio to offload the duty of verifying I/O |
| contents to one or more separate threads. If using this offload option, even |
| sync I/O engines can benefit from using an \fBiodepth\fR setting higher |
| than 1, as it allows them to have I/O in flight while verifies are running. |
| Defaults to 0 async threads, i.e. verification is not asynchronous. |
| .TP |
| .BI verify_async_cpus \fR=\fPstr |
| Tell fio to set the given CPU affinity on the async I/O verification |
| threads. See \fBcpus_allowed\fR for the format used. |
| .TP |
| .BI verify_backlog \fR=\fPint |
| Fio will normally verify the written contents of a job that utilizes verify |
| once that job has completed. In other words, everything is written then |
| everything is read back and verified. You may want to verify continually |
| instead for a variety of reasons. Fio stores the meta data associated with |
| an I/O block in memory, so for large verify workloads, quite a bit of memory |
| would be used up holding this meta data. If this option is enabled, fio will |
| write only N blocks before verifying these blocks. |
| .TP |
| .BI verify_backlog_batch \fR=\fPint |
| Control how many blocks fio will verify if \fBverify_backlog\fR is |
| set. If not set, will default to the value of \fBverify_backlog\fR |
| (meaning the entire queue is read back and verified). If |
| \fBverify_backlog_batch\fR is less than \fBverify_backlog\fR then not all |
| blocks will be verified, if \fBverify_backlog_batch\fR is larger than |
| \fBverify_backlog\fR, some blocks will be verified more than once. |
| .TP |
| .BI verify_state_save \fR=\fPbool |
| When a job exits during the write phase of a verify workload, save its |
| current state. This allows fio to replay up until that point, if the verify |
| state is loaded for the verify read phase. The format of the filename is, |
| roughly: |
| .RS |
| .RS |
| .P |
| <type>\-<jobname>\-<jobindex>\-verify.state. |
| .RE |
| .P |
| <type> is "local" for a local run, "sock" for a client/server socket |
| connection, and "ip" (192.168.0.1, for instance) for a networked |
| client/server connection. Defaults to true. |
| .RE |
| .TP |
| .BI verify_state_load \fR=\fPbool |
| If a verify termination trigger was used, fio stores the current write state |
| of each thread. This can be used at verification time so that fio knows how |
| far it should verify. Without this information, fio will run a full |
| verification pass, according to the settings in the job file used. Default |
| false. |
| .TP |
| .BI trim_percentage \fR=\fPint |
| Number of verify blocks to discard/trim. |
| .TP |
| .BI trim_verify_zero \fR=\fPbool |
| Verify that trim/discarded blocks are returned as zeros. |
| .TP |
| .BI trim_backlog \fR=\fPint |
| Verify that trim/discarded blocks are returned as zeros. |
| .TP |
| .BI trim_backlog_batch \fR=\fPint |
| Trim this number of I/O blocks. |
| .TP |
| .BI experimental_verify \fR=\fPbool |
| Enable experimental verification. |
| .SS "Steady state" |
| .TP |
| .BI steadystate \fR=\fPstr:float "\fR,\fP ss" \fR=\fPstr:float |
| Define the criterion and limit for assessing steady state performance. The |
| first parameter designates the criterion whereas the second parameter sets |
| the threshold. When the criterion falls below the threshold for the |
| specified duration, the job will stop. For example, `iops_slope:0.1%' will |
| direct fio to terminate the job when the least squares regression slope |
| falls below 0.1% of the mean IOPS. If \fBgroup_reporting\fR is enabled |
| this will apply to all jobs in the group. Below is the list of available |
| steady state assessment criteria. All assessments are carried out using only |
| data from the rolling collection window. Threshold limits can be expressed |
| as a fixed value or as a percentage of the mean in the collection window. |
| .RS |
| .P |
| When using this feature, most jobs should include the \fBtime_based\fR |
| and \fBruntime\fR options or the \fBloops\fR option so that fio does not |
| stop running after it has covered the full size of the specified file(s) |
| or device(s). |
| .RS |
| .RS |
| .TP |
| .B iops |
| Collect IOPS data. Stop the job if all individual IOPS measurements |
| are within the specified limit of the mean IOPS (e.g., `iops:2' |
| means that all individual IOPS values must be within 2 of the mean, |
| whereas `iops:0.2%' means that all individual IOPS values must be |
| within 0.2% of the mean IOPS to terminate the job). |
| .TP |
| .B iops_slope |
| Collect IOPS data and calculate the least squares regression |
| slope. Stop the job if the slope falls below the specified limit. |
| .TP |
| .B bw |
| Collect bandwidth data. Stop the job if all individual bandwidth |
| measurements are within the specified limit of the mean bandwidth. |
| .TP |
| .B bw_slope |
| Collect bandwidth data and calculate the least squares regression |
| slope. Stop the job if the slope falls below the specified limit. |
| .RE |
| .RE |
| .TP |
| .BI steadystate_duration \fR=\fPtime "\fR,\fP ss_dur" \fR=\fPtime |
| A rolling window of this duration will be used to judge whether steady state |
| has been reached. Data will be collected once per second. The default is 0 |
| which disables steady state detection. When the unit is omitted, the |
| value is interpreted in seconds. |
| .TP |
| .BI steadystate_ramp_time \fR=\fPtime "\fR,\fP ss_ramp" \fR=\fPtime |
| Allow the job to run for the specified duration before beginning data |
| collection for checking the steady state job termination criterion. The |
| default is 0. When the unit is omitted, the value is interpreted in seconds. |
| .SS "Measurements and reporting" |
| .TP |
| .BI per_job_logs \fR=\fPbool |
| If set, this generates bw/clat/iops log with per file private filenames. If |
| not set, jobs with identical names will share the log filename. Default: |
| true. |
| .TP |
| .BI group_reporting |
| It may sometimes be interesting to display statistics for groups of jobs as |
| a whole instead of for each individual job. This is especially true if |
| \fBnumjobs\fR is used; looking at individual thread/process output |
| quickly becomes unwieldy. To see the final report per-group instead of |
| per-job, use \fBgroup_reporting\fR. Jobs in a file will be part of the |
| same reporting group, unless if separated by a \fBstonewall\fR, or by |
| using \fBnew_group\fR. |
| .TP |
| .BI new_group |
| Start a new reporting group. See: \fBgroup_reporting\fR. If not given, |
| all jobs in a file will be part of the same reporting group, unless |
| separated by a \fBstonewall\fR. |
| .TP |
| .BI stats \fR=\fPbool |
| By default, fio collects and shows final output results for all jobs |
| that run. If this option is set to 0, then fio will ignore it in |
| the final stat output. |
| .TP |
| .BI write_bw_log \fR=\fPstr |
| If given, write a bandwidth log for this job. Can be used to store data of |
| the bandwidth of the jobs in their lifetime. |
| .RS |
| .P |
| If no str argument is given, the default filename of |
| `jobname_type.x.log' is used. Even when the argument is given, fio |
| will still append the type of log. So if one specifies: |
| .RS |
| .P |
| write_bw_log=foo |
| .RE |
| .P |
| The actual log name will be `foo_bw.x.log' where `x' is the index |
| of the job (1..N, where N is the number of jobs). If |
| \fBper_job_logs\fR is false, then the filename will not include the |
| `.x` job index. |
| .P |
| The included \fBfio_generate_plots\fR script uses gnuplot to turn these |
| text files into nice graphs. See the \fBLOG FILE FORMATS\fR section for how data is |
| structured within the file. |
| .RE |
| .TP |
| .BI write_lat_log \fR=\fPstr |
| Same as \fBwrite_bw_log\fR, except this option creates I/O |
| submission (e.g., `name_slat.x.log'), completion (e.g., |
| `name_clat.x.log'), and total (e.g., `name_lat.x.log') latency |
| files instead. See \fBwrite_bw_log\fR for details about the |
| filename format and the \fBLOG FILE FORMATS\fR section for how data is structured |
| within the files. |
| .TP |
| .BI write_hist_log \fR=\fPstr |
| Same as \fBwrite_bw_log\fR but writes an I/O completion latency |
| histogram file (e.g., `name_hist.x.log') instead. Note that this |
| file will be empty unless \fBlog_hist_msec\fR has also been set. |
| See \fBwrite_bw_log\fR for details about the filename format and |
| the \fBLOG FILE FORMATS\fR section for how data is structured |
| within the file. |
| .TP |
| .BI write_iops_log \fR=\fPstr |
| Same as \fBwrite_bw_log\fR, but writes an IOPS file (e.g. |
| `name_iops.x.log`) instead. Because fio defaults to individual |
| I/O logging, the value entry in the IOPS log will be 1 unless windowed |
| logging (see \fBlog_avg_msec\fR) has been enabled. See |
| \fBwrite_bw_log\fR for details about the filename format and \fBLOG |
| FILE FORMATS\fR for how data is structured within the file. |
| .TP |
| .BI log_avg_msec \fR=\fPint |
| By default, fio will log an entry in the iops, latency, or bw log for every |
| I/O that completes. When writing to the disk log, that can quickly grow to a |
| very large size. Setting this option makes fio average the each log entry |
| over the specified period of time, reducing the resolution of the log. See |
| \fBlog_max_value\fR as well. Defaults to 0, logging all entries. |
| Also see \fBLOG FILE FORMATS\fR section. |
| .TP |
| .BI log_hist_msec \fR=\fPint |
| Same as \fBlog_avg_msec\fR, but logs entries for completion latency |
| histograms. Computing latency percentiles from averages of intervals using |
| \fBlog_avg_msec\fR is inaccurate. Setting this option makes fio log |
| histogram entries over the specified period of time, reducing log sizes for |
| high IOPS devices while retaining percentile accuracy. See |
| \fBlog_hist_coarseness\fR and \fBwrite_hist_log\fR as well. |
| Defaults to 0, meaning histogram logging is disabled. |
| .TP |
| .BI log_hist_coarseness \fR=\fPint |
| Integer ranging from 0 to 6, defining the coarseness of the resolution of |
| the histogram logs enabled with \fBlog_hist_msec\fR. For each increment |
| in coarseness, fio outputs half as many bins. Defaults to 0, for which |
| histogram logs contain 1216 latency bins. See \fBLOG FILE FORMATS\fR section. |
| .TP |
| .BI log_max_value \fR=\fPbool |
| If \fBlog_avg_msec\fR is set, fio logs the average over that window. If |
| you instead want to log the maximum value, set this option to 1. Defaults to |
| 0, meaning that averaged values are logged. |
| .TP |
| .BI log_offset \fR=\fPbool |
| If this is set, the iolog options will include the byte offset for the I/O |
| entry as well as the other data values. Defaults to 0 meaning that |
| offsets are not present in logs. Also see \fBLOG FILE FORMATS\fR section. |
| .TP |
| .BI log_compression \fR=\fPint |
| If this is set, fio will compress the I/O logs as it goes, to keep the |
| memory footprint lower. When a log reaches the specified size, that chunk is |
| removed and compressed in the background. Given that I/O logs are fairly |
| highly compressible, this yields a nice memory savings for longer runs. The |
| downside is that the compression will consume some background CPU cycles, so |
| it may impact the run. This, however, is also true if the logging ends up |
| consuming most of the system memory. So pick your poison. The I/O logs are |
| saved normally at the end of a run, by decompressing the chunks and storing |
| them in the specified log file. This feature depends on the availability of |
| zlib. |
| .TP |
| .BI log_compression_cpus \fR=\fPstr |
| Define the set of CPUs that are allowed to handle online log compression for |
| the I/O jobs. This can provide better isolation between performance |
| sensitive jobs, and background compression work. See \fBcpus_allowed\fR for |
| the format used. |
| .TP |
| .BI log_store_compressed \fR=\fPbool |
| If set, fio will store the log files in a compressed format. They can be |
| decompressed with fio, using the \fB\-\-inflate\-log\fR command line |
| parameter. The files will be stored with a `.fz' suffix. |
| .TP |
| .BI log_unix_epoch \fR=\fPbool |
| If set, fio will log Unix timestamps to the log files produced by enabling |
| write_type_log for each log type, instead of the default zero-based |
| timestamps. |
| .TP |
| .BI block_error_percentiles \fR=\fPbool |
| If set, record errors in trim block-sized units from writes and trims and |
| output a histogram of how many trims it took to get to errors, and what kind |
| of error was encountered. |
| .TP |
| .BI bwavgtime \fR=\fPint |
| Average the calculated bandwidth over the given time. Value is specified in |
| milliseconds. If the job also does bandwidth logging through |
| \fBwrite_bw_log\fR, then the minimum of this option and |
| \fBlog_avg_msec\fR will be used. Default: 500ms. |
| .TP |
| .BI iopsavgtime \fR=\fPint |
| Average the calculated IOPS over the given time. Value is specified in |
| milliseconds. If the job also does IOPS logging through |
| \fBwrite_iops_log\fR, then the minimum of this option and |
| \fBlog_avg_msec\fR will be used. Default: 500ms. |
| .TP |
| .BI disk_util \fR=\fPbool |
| Generate disk utilization statistics, if the platform supports it. |
| Default: true. |
| .TP |
| .BI disable_lat \fR=\fPbool |
| Disable measurements of total latency numbers. Useful only for cutting back |
| the number of calls to \fBgettimeofday\fR\|(2), as that does impact |
| performance at really high IOPS rates. Note that to really get rid of a |
| large amount of these calls, this option must be used with |
| \fBdisable_slat\fR and \fBdisable_bw_measurement\fR as well. |
| .TP |
| .BI disable_clat \fR=\fPbool |
| Disable measurements of completion latency numbers. See |
| \fBdisable_lat\fR. |
| .TP |
| .BI disable_slat \fR=\fPbool |
| Disable measurements of submission latency numbers. See |
| \fBdisable_lat\fR. |
| .TP |
| .BI disable_bw_measurement \fR=\fPbool "\fR,\fP disable_bw" \fR=\fPbool |
| Disable measurements of throughput/bandwidth numbers. See |
| \fBdisable_lat\fR. |
| .TP |
| .BI slat_percentiles \fR=\fPbool |
| Report submission latency percentiles. Submission latency is not recorded |
| for synchronous ioengines. |
| .TP |
| .BI clat_percentiles \fR=\fPbool |
| Report completion latency percentiles. |
| .TP |
| .BI lat_percentiles \fR=\fPbool |
| Report total latency percentiles. Total latency is the sum of submission |
| latency and completion latency. |
| .TP |
| .BI percentile_list \fR=\fPfloat_list |
| Overwrite the default list of percentiles for latencies and the |
| block error histogram. Each number is a floating point number in the range |
| (0,100], and the maximum length of the list is 20. Use ':' to separate the |
| numbers. For example, `\-\-percentile_list=99.5:99.9' will cause fio to |
| report the latency durations below which 99.5% and 99.9% of the observed |
| latencies fell, respectively. |
| .TP |
| .BI significant_figures \fR=\fPint |
| If using \fB\-\-output\-format\fR of `normal', set the significant figures |
| to this value. Higher values will yield more precise IOPS and throughput |
| units, while lower values will round. Requires a minimum value of 1 and a |
| maximum value of 10. Defaults to 4. |
| .SS "Error handling" |
| .TP |
| .BI exitall_on_error |
| When one job finishes in error, terminate the rest. The default is to wait |
| for each job to finish. |
| .TP |
| .BI continue_on_error \fR=\fPstr |
| Normally fio will exit the job on the first observed failure. If this option |
| is set, fio will continue the job when there is a 'non-fatal error' (EIO or |
| EILSEQ) until the runtime is exceeded or the I/O size specified is |
| completed. If this option is used, there are two more stats that are |
| appended, the total error count and the first error. The error field given |
| in the stats is the first error that was hit during the run. |
| The allowed values are: |
| .RS |
| .RS |
| .TP |
| .B none |
| Exit on any I/O or verify errors. |
| .TP |
| .B read |
| Continue on read errors, exit on all others. |
| .TP |
| .B write |
| Continue on write errors, exit on all others. |
| .TP |
| .B io |
| Continue on any I/O error, exit on all others. |
| .TP |
| .B verify |
| Continue on verify errors, exit on all others. |
| .TP |
| .B all |
| Continue on all errors. |
| .TP |
| .B 0 |
| Backward-compatible alias for 'none'. |
| .TP |
| .B 1 |
| Backward-compatible alias for 'all'. |
| .RE |
| .RE |
| .TP |
| .BI ignore_error \fR=\fPstr |
| Sometimes you want to ignore some errors during test in that case you can |
| specify error list for each error type, instead of only being able to |
| ignore the default 'non-fatal error' using \fBcontinue_on_error\fR. |
| `ignore_error=READ_ERR_LIST,WRITE_ERR_LIST,VERIFY_ERR_LIST' errors for |
| given error type is separated with ':'. Error may be symbol ('ENOSPC', 'ENOMEM') |
| or integer. Example: |
| .RS |
| .RS |
| .P |
| ignore_error=EAGAIN,ENOSPC:122 |
| .RE |
| .P |
| This option will ignore EAGAIN from READ, and ENOSPC and 122(EDQUOT) from |
| WRITE. This option works by overriding \fBcontinue_on_error\fR with |
| the list of errors for each error type if any. |
| .RE |
| .TP |
| .BI error_dump \fR=\fPbool |
| If set dump every error even if it is non fatal, true by default. If |
| disabled only fatal error will be dumped. |
| .SS "Running predefined workloads" |
| Fio includes predefined profiles that mimic the I/O workloads generated by |
| other tools. |
| .TP |
| .BI profile \fR=\fPstr |
| The predefined workload to run. Current profiles are: |
| .RS |
| .RS |
| .TP |
| .B tiobench |
| Threaded I/O bench (tiotest/tiobench) like workload. |
| .TP |
| .B act |
| Aerospike Certification Tool (ACT) like workload. |
| .RE |
| .RE |
| .P |
| To view a profile's additional options use \fB\-\-cmdhelp\fR after specifying |
| the profile. For example: |
| .RS |
| .TP |
| $ fio \-\-profile=act \-\-cmdhelp |
| .RE |
| .SS "Act profile options" |
| .TP |
| .BI device\-names \fR=\fPstr |
| Devices to use. |
| .TP |
| .BI load \fR=\fPint |
| ACT load multiplier. Default: 1. |
| .TP |
| .BI test\-duration\fR=\fPtime |
| How long the entire test takes to run. When the unit is omitted, the value |
| is given in seconds. Default: 24h. |
| .TP |
| .BI threads\-per\-queue\fR=\fPint |
| Number of read I/O threads per device. Default: 8. |
| .TP |
| .BI read\-req\-num\-512\-blocks\fR=\fPint |
| Number of 512B blocks to read at the time. Default: 3. |
| .TP |
| .BI large\-block\-op\-kbytes\fR=\fPint |
| Size of large block ops in KiB (writes). Default: 131072. |
| .TP |
| .BI prep |
| Set to run ACT prep phase. |
| .SS "Tiobench profile options" |
| .TP |
| .BI size\fR=\fPstr |
| Size in MiB. |
| .TP |
| .BI block\fR=\fPint |
| Block size in bytes. Default: 4096. |
| .TP |
| .BI numruns\fR=\fPint |
| Number of runs. |
| .TP |
| .BI dir\fR=\fPstr |
| Test directory. |
| .TP |
| .BI threads\fR=\fPint |
| Number of threads. |
| .SH OUTPUT |
| Fio spits out a lot of output. While running, fio will display the status of the |
| jobs created. An example of that would be: |
| .P |
| .nf |
| Jobs: 1 (f=1): [_(1),M(1)][24.8%][r=20.5MiB/s,w=23.5MiB/s][r=82,w=94 IOPS][eta 01m:31s] |
| .fi |
| .P |
| The characters inside the first set of square brackets denote the current status of |
| each thread. The first character is the first job defined in the job file, and so |
| forth. The possible values (in typical life cycle order) are: |
| .RS |
| .TP |
| .PD 0 |
| .B P |
| Thread setup, but not started. |
| .TP |
| .B C |
| Thread created. |
| .TP |
| .B I |
| Thread initialized, waiting or generating necessary data. |
| .TP |
| .B p |
| Thread running pre-reading file(s). |
| .TP |
| .B / |
| Thread is in ramp period. |
| .TP |
| .B R |
| Running, doing sequential reads. |
| .TP |
| .B r |
| Running, doing random reads. |
| .TP |
| .B W |
| Running, doing sequential writes. |
| .TP |
| .B w |
| Running, doing random writes. |
| .TP |
| .B M |
| Running, doing mixed sequential reads/writes. |
| .TP |
| .B m |
| Running, doing mixed random reads/writes. |
| .TP |
| .B D |
| Running, doing sequential trims. |
| .TP |
| .B d |
| Running, doing random trims. |
| .TP |
| .B F |
| Running, currently waiting for \fBfsync\fR\|(2). |
| .TP |
| .B V |
| Running, doing verification of written data. |
| .TP |
| .B f |
| Thread finishing. |
| .TP |
| .B E |
| Thread exited, not reaped by main thread yet. |
| .TP |
| .B \- |
| Thread reaped. |
| .TP |
| .B X |
| Thread reaped, exited with an error. |
| .TP |
| .B K |
| Thread reaped, exited due to signal. |
| .PD |
| .RE |
| .P |
| Fio will condense the thread string as not to take up more space on the command |
| line than needed. For instance, if you have 10 readers and 10 writers running, |
| the output would look like this: |
| .P |
| .nf |
| Jobs: 20 (f=20): [R(10),W(10)][4.0%][r=20.5MiB/s,w=23.5MiB/s][r=82,w=94 IOPS][eta 57m:36s] |
| .fi |
| .P |
| Note that the status string is displayed in order, so it's possible to tell which of |
| the jobs are currently doing what. In the example above this means that jobs 1\-\-10 |
| are readers and 11\-\-20 are writers. |
| .P |
| The other values are fairly self explanatory \-\- number of threads currently |
| running and doing I/O, the number of currently open files (f=), the estimated |
| completion percentage, the rate of I/O since last check (read speed listed first, |
| then write speed and optionally trim speed) in terms of bandwidth and IOPS, |
| and time to completion for the current running group. It's impossible to estimate |
| runtime of the following groups (if any). |
| .P |
| When fio is done (or interrupted by Ctrl\-C), it will show the data for |
| each thread, group of threads, and disks in that order. For each overall thread (or |
| group) the output looks like: |
| .P |
| .nf |
| Client1: (groupid=0, jobs=1): err= 0: pid=16109: Sat Jun 24 12:07:54 2017 |
| write: IOPS=88, BW=623KiB/s (638kB/s)(30.4MiB/50032msec) |
| slat (nsec): min=500, max=145500, avg=8318.00, stdev=4781.50 |
| clat (usec): min=170, max=78367, avg=4019.02, stdev=8293.31 |
| lat (usec): min=174, max=78375, avg=4027.34, stdev=8291.79 |
| clat percentiles (usec): |
| | 1.00th=[ 302], 5.00th=[ 326], 10.00th=[ 343], 20.00th=[ 363], |
| | 30.00th=[ 392], 40.00th=[ 404], 50.00th=[ 416], 60.00th=[ 445], |
| | 70.00th=[ 816], 80.00th=[ 6718], 90.00th=[12911], 95.00th=[21627], |
| | 99.00th=[43779], 99.50th=[51643], 99.90th=[68682], 99.95th=[72877], |
| | 99.99th=[78119] |
| bw ( KiB/s): min= 532, max= 686, per=0.10%, avg=622.87, stdev=24.82, samples= 100 |
| iops : min= 76, max= 98, avg=88.98, stdev= 3.54, samples= 100 |
| lat (usec) : 250=0.04%, 500=64.11%, 750=4.81%, 1000=2.79% |
| lat (msec) : 2=4.16%, 4=1.84%, 10=4.90%, 20=11.33%, 50=5.37% |
| lat (msec) : 100=0.65% |
| cpu : usr=0.27%, sys=0.18%, ctx=12072, majf=0, minf=21 |
| IO depths : 1=85.0%, 2=13.1%, 4=1.8%, 8=0.1%, 16=0.0%, 32=0.0%, >=64=0.0% |
| submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0% |
| complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0% |
| issued rwt: total=0,4450,0, short=0,0,0, dropped=0,0,0 |
| latency : target=0, window=0, percentile=100.00%, depth=8 |
| .fi |
| .P |
| The job name (or first job's name when using \fBgroup_reporting\fR) is printed, |
| along with the group id, count of jobs being aggregated, last error id seen (which |
| is 0 when there are no errors), pid/tid of that thread and the time the job/group |
| completed. Below are the I/O statistics for each data direction performed (showing |
| writes in the example above). In the order listed, they denote: |
| .RS |
| .TP |
| .B read/write/trim |
| The string before the colon shows the I/O direction the statistics |
| are for. \fIIOPS\fR is the average I/Os performed per second. \fIBW\fR |
| is the average bandwidth rate shown as: value in power of 2 format |
| (value in power of 10 format). The last two values show: (total |
| I/O performed in power of 2 format / \fIruntime\fR of that thread). |
| .TP |
| .B slat |
| Submission latency (\fImin\fR being the minimum, \fImax\fR being the |
| maximum, \fIavg\fR being the average, \fIstdev\fR being the standard |
| deviation). This is the time it took to submit the I/O. For |
| sync I/O this row is not displayed as the slat is really the |
| completion latency (since queue/complete is one operation there). |
| This value can be in nanoseconds, microseconds or milliseconds \-\-\- |
| fio will choose the most appropriate base and print that (in the |
| example above nanoseconds was the best scale). Note: in \fB\-\-minimal\fR mode |
| latencies are always expressed in microseconds. |
| .TP |
| .B clat |
| Completion latency. Same names as slat, this denotes the time from |
| submission to completion of the I/O pieces. For sync I/O, clat will |
| usually be equal (or very close) to 0, as the time from submit to |
| complete is basically just CPU time (I/O has already been done, see slat |
| explanation). |
| .TP |
| .B lat |
| Total latency. Same names as slat and clat, this denotes the time from |
| when fio created the I/O unit to completion of the I/O operation. |
| .TP |
| .B bw |
| Bandwidth statistics based on samples. Same names as the xlat stats, |
| but also includes the number of samples taken (\fIsamples\fR) and an |
| approximate percentage of total aggregate bandwidth this thread |
| received in its group (\fIper\fR). This last value is only really |
| useful if the threads in this group are on the same disk, since they |
| are then competing for disk access. |
| .TP |
| .B iops |
| IOPS statistics based on samples. Same names as \fBbw\fR. |
| .TP |
| .B lat (nsec/usec/msec) |
| The distribution of I/O completion latencies. This is the time from when |
| I/O leaves fio and when it gets completed. Unlike the separate |
| read/write/trim sections above, the data here and in the remaining |
| sections apply to all I/Os for the reporting group. 250=0.04% means that |
| 0.04% of the I/Os completed in under 250us. 500=64.11% means that 64.11% |
| of the I/Os required 250 to 499us for completion. |
| .TP |
| .B cpu |
| CPU usage. User and system time, along with the number of context |
| switches this thread went through, usage of system and user time, and |
| finally the number of major and minor page faults. The CPU utilization |
| numbers are averages for the jobs in that reporting group, while the |
| context and fault counters are summed. |
| .TP |
| .B IO depths |
| The distribution of I/O depths over the job lifetime. The numbers are |
| divided into powers of 2 and each entry covers depths from that value |
| up to those that are lower than the next entry \-\- e.g., 16= covers |
| depths from 16 to 31. Note that the range covered by a depth |
| distribution entry can be different to the range covered by the |
| equivalent \fBsubmit\fR/\fBcomplete\fR distribution entry. |
| .TP |
| .B IO submit |
| How many pieces of I/O were submitting in a single submit call. Each |
| entry denotes that amount and below, until the previous entry \-\- e.g., |
| 16=100% means that we submitted anywhere between 9 to 16 I/Os per submit |
| call. Note that the range covered by a \fBsubmit\fR distribution entry can |
| be different to the range covered by the equivalent depth distribution |
| entry. |
| .TP |
| .B IO complete |
| Like the above \fBsubmit\fR number, but for completions instead. |
| .TP |
| .B IO issued rwt |
| The number of \fBread/write/trim\fR requests issued, and how many of them were |
| short or dropped. |
| .TP |
| .B IO latency |
| These values are for \fBlatency_target\fR and related options. When |
| these options are engaged, this section describes the I/O depth required |
| to meet the specified latency target. |
| .RE |
| .P |
| After each client has been listed, the group statistics are printed. They |
| will look like this: |
| .P |
| .nf |
| Run status group 0 (all jobs): |
| READ: bw=20.9MiB/s (21.9MB/s), 10.4MiB/s\-10.8MiB/s (10.9MB/s\-11.3MB/s), io=64.0MiB (67.1MB), run=2973\-3069msec |
| WRITE: bw=1231KiB/s (1261kB/s), 616KiB/s\-621KiB/s (630kB/s\-636kB/s), io=64.0MiB (67.1MB), run=52747\-53223msec |
| .fi |
| .P |
| For each data direction it prints: |
| .RS |
| .TP |
| .B bw |
| Aggregate bandwidth of threads in this group followed by the |
| minimum and maximum bandwidth of all the threads in this group. |
| Values outside of brackets are power-of-2 format and those |
| within are the equivalent value in a power-of-10 format. |
| .TP |
| .B io |
| Aggregate I/O performed of all threads in this group. The |
| format is the same as \fBbw\fR. |
| .TP |
| .B run |
| The smallest and longest runtimes of the threads in this group. |
| .RE |
| .P |
| And finally, the disk statistics are printed. This is Linux specific. |
| They will look like this: |
| .P |
| .nf |
| Disk stats (read/write): |
| sda: ios=16398/16511, merge=30/162, ticks=6853/819634, in_queue=826487, util=100.00% |
| .fi |
| .P |
| Each value is printed for both reads and writes, with reads first. The |
| numbers denote: |
| .RS |
| .TP |
| .B ios |
| Number of I/Os performed by all groups. |
| .TP |
| .B merge |
| Number of merges performed by the I/O scheduler. |
| .TP |
| .B ticks |
| Number of ticks we kept the disk busy. |
| .TP |
| .B in_queue |
| Total time spent in the disk queue. |
| .TP |
| .B util |
| The disk utilization. A value of 100% means we kept the disk |
| busy constantly, 50% would be a disk idling half of the time. |
| .RE |
| .P |
| It is also possible to get fio to dump the current output while it is running, |
| without terminating the job. To do that, send fio the USR1 signal. You can |
| also get regularly timed dumps by using the \fB\-\-status\-interval\fR |
| parameter, or by creating a file in `/tmp' named |
| `fio\-dump\-status'. If fio sees this file, it will unlink it and dump the |
| current output status. |
| .SH TERSE OUTPUT |
| For scripted usage where you typically want to generate tables or graphs of the |
| results, fio can output the results in a semicolon separated format. The format |
| is one long line of values, such as: |
| .P |
| .nf |
| 2;card0;0;0;7139336;121836;60004;1;10109;27.932460;116.933948;220;126861;3495.446807;1085.368601;226;126864;3523.635629;1089.012448;24063;99944;50.275485%;59818.274627;5540.657370;7155060;122104;60004;1;8338;29.086342;117.839068;388;128077;5032.488518;1234.785715;391;128085;5061.839412;1236.909129;23436;100928;50.287926%;59964.832030;5644.844189;14.595833%;19.394167%;123706;0;7313;0.1%;0.1%;0.1%;0.1%;0.1%;0.1%;100.0%;0.00%;0.00%;0.00%;0.00%;0.00%;0.00%;0.01%;0.02%;0.05%;0.16%;6.04%;40.40%;52.68%;0.64%;0.01%;0.00%;0.01%;0.00%;0.00%;0.00%;0.00%;0.00% |
| A description of this job goes here. |
| .fi |
| .P |
| The job description (if provided) follows on a second line for terse v2. |
| It appears on the same line for other terse versions. |
| .P |
| To enable terse output, use the \fB\-\-minimal\fR or |
| `\-\-output\-format=terse' command line options. The |
| first value is the version of the terse output format. If the output has to be |
| changed for some reason, this number will be incremented by 1 to signify that |
| change. |
| .P |
| Split up, the format is as follows (comments in brackets denote when a |
| field was introduced or whether it's specific to some terse version): |
| .P |
| .nf |
| terse version, fio version [v3], jobname, groupid, error |
| .fi |
| .RS |
| .P |
| .B |
| READ status: |
| .RE |
| .P |
| .nf |
| Total IO (KiB), bandwidth (KiB/sec), IOPS, runtime (msec) |
| Submission latency: min, max, mean, stdev (usec) |
| Completion latency: min, max, mean, stdev (usec) |
| Completion latency percentiles: 20 fields (see below) |
| Total latency: min, max, mean, stdev (usec) |
| Bw (KiB/s): min, max, aggregate percentage of total, mean, stdev, number of samples [v5] |
| IOPS [v5]: min, max, mean, stdev, number of samples |
| .fi |
| .RS |
| .P |
| .B |
| WRITE status: |
| .RE |
| .P |
| .nf |
| Total IO (KiB), bandwidth (KiB/sec), IOPS, runtime (msec) |
| Submission latency: min, max, mean, stdev (usec) |
| Completion latency: min, max, mean, stdev (usec) |
| Completion latency percentiles: 20 fields (see below) |
| Total latency: min, max, mean, stdev (usec) |
| Bw (KiB/s): min, max, aggregate percentage of total, mean, stdev, number of samples [v5] |
| IOPS [v5]: min, max, mean, stdev, number of samples |
| .fi |
| .RS |
| .P |
| .B |
| TRIM status [all but version 3]: |
| .RE |
| .P |
| .nf |
| Fields are similar to \fBREAD/WRITE\fR status. |
| .fi |
| .RS |
| .P |
| .B |
| CPU usage: |
| .RE |
| .P |
| .nf |
| user, system, context switches, major faults, minor faults |
| .fi |
| .RS |
| .P |
| .B |
| I/O depths: |
| .RE |
| .P |
| .nf |
| <=1, 2, 4, 8, 16, 32, >=64 |
| .fi |
| .RS |
| .P |
| .B |
| I/O latencies microseconds: |
| .RE |
| .P |
| .nf |
| <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000 |
| .fi |
| .RS |
| .P |
| .B |
| I/O latencies milliseconds: |
| .RE |
| .P |
| .nf |
| <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000, 2000, >=2000 |
| .fi |
| .RS |
| .P |
| .B |
| Disk utilization [v3]: |
| .RE |
| .P |
| .nf |
| disk name, read ios, write ios, read merges, write merges, read ticks, write ticks, time spent in queue, disk utilization percentage |
| .fi |
| .RS |
| .P |
| .B |
| Additional Info (dependent on continue_on_error, default off): |
| .RE |
| .P |
| .nf |
| total # errors, first error code |
| .fi |
| .RS |
| .P |
| .B |
| Additional Info (dependent on description being set): |
| .RE |
| .P |
| .nf |
| Text description |
| .fi |
| .P |
| Completion latency percentiles can be a grouping of up to 20 sets, so for the |
| terse output fio writes all of them. Each field will look like this: |
| .P |
| .nf |
| 1.00%=6112 |
| .fi |
| .P |
| which is the Xth percentile, and the `usec' latency associated with it. |
| .P |
| For \fBDisk utilization\fR, all disks used by fio are shown. So for each disk there |
| will be a disk utilization section. |
| .P |
| Below is a single line containing short names for each of the fields in the |
| minimal output v3, separated by semicolons: |
| .P |
| .nf |
| terse_version_3;fio_version;jobname;groupid;error;read_kb;read_bandwidth;read_iops;read_runtime_ms;read_slat_min;read_slat_max;read_slat_mean;read_slat_dev;read_clat_min;read_clat_max;read_clat_mean;read_clat_dev;read_clat_pct01;read_clat_pct02;read_clat_pct03;read_clat_pct04;read_clat_pct05;read_clat_pct06;read_clat_pct07;read_clat_pct08;read_clat_pct09;read_clat_pct10;read_clat_pct11;read_clat_pct12;read_clat_pct13;read_clat_pct14;read_clat_pct15;read_clat_pct16;read_clat_pct17;read_clat_pct18;read_clat_pct19;read_clat_pct20;read_tlat_min;read_lat_max;read_lat_mean;read_lat_dev;read_bw_min;read_bw_max;read_bw_agg_pct;read_bw_mean;read_bw_dev;write_kb;write_bandwidth;write_iops;write_runtime_ms;write_slat_min;write_slat_max;write_slat_mean;write_slat_dev;write_clat_min;write_clat_max;write_clat_mean;write_clat_dev;write_clat_pct01;write_clat_pct02;write_clat_pct03;write_clat_pct04;write_clat_pct05;write_clat_pct06;write_clat_pct07;write_clat_pct08;write_clat_pct09;write_clat_pct10;write_clat_pct11;write_clat_pct12;write_clat_pct13;write_clat_pct14;write_clat_pct15;write_clat_pct16;write_clat_pct17;write_clat_pct18;write_clat_pct19;write_clat_pct20;write_tlat_min;write_lat_max;write_lat_mean;write_lat_dev;write_bw_min;write_bw_max;write_bw_agg_pct;write_bw_mean;write_bw_dev;cpu_user;cpu_sys;cpu_csw;cpu_mjf;cpu_minf;iodepth_1;iodepth_2;iodepth_4;iodepth_8;iodepth_16;iodepth_32;iodepth_64;lat_2us;lat_4us;lat_10us;lat_20us;lat_50us;lat_100us;lat_250us;lat_500us;lat_750us;lat_1000us;lat_2ms;lat_4ms;lat_10ms;lat_20ms;lat_50ms;lat_100ms;lat_250ms;lat_500ms;lat_750ms;lat_1000ms;lat_2000ms;lat_over_2000ms;disk_name;disk_read_iops;disk_write_iops;disk_read_merges;disk_write_merges;disk_read_ticks;write_ticks;disk_queue_time;disk_util |
| .fi |
| .P |
| In client/server mode terse output differs from what appears when jobs are run |
| locally. Disk utilization data is omitted from the standard terse output and |
| for v3 and later appears on its own separate line at the end of each terse |
| reporting cycle. |
| .SH JSON OUTPUT |
| The \fBjson\fR output format is intended to be both human readable and convenient |
| for automated parsing. For the most part its sections mirror those of the |
| \fBnormal\fR output. The \fBruntime\fR value is reported in msec and the \fBbw\fR value is |
| reported in 1024 bytes per second units. |
| .fi |
| .SH JSON+ OUTPUT |
| The \fBjson+\fR output format is identical to the \fBjson\fR output format except that it |
| adds a full dump of the completion latency bins. Each \fBbins\fR object contains a |
| set of (key, value) pairs where keys are latency durations and values count how |
| many I/Os had completion latencies of the corresponding duration. For example, |
| consider: |
| .RS |
| .P |
| "bins" : { "87552" : 1, "89600" : 1, "94720" : 1, "96768" : 1, "97792" : 1, "99840" : 1, "100864" : 2, "103936" : 6, "104960" : 534, "105984" : 5995, "107008" : 7529, ... } |
| .RE |
| .P |
| This data indicates that one I/O required 87,552ns to complete, two I/Os required |
| 100,864ns to complete, and 7529 I/Os required 107,008ns to complete. |
| .P |
| Also included with fio is a Python script \fBfio_jsonplus_clat2csv\fR that takes |
| json+ output and generates CSV-formatted latency data suitable for plotting. |
| .P |
| The latency durations actually represent the midpoints of latency intervals. |
| For details refer to `stat.h' in the fio source. |
| .SH TRACE FILE FORMAT |
| There are two trace file format that you can encounter. The older (v1) format is |
| unsupported since version 1.20\-rc3 (March 2008). It will still be described |
| below in case that you get an old trace and want to understand it. |
| .P |
| In any case the trace is a simple text file with a single action per line. |
| .TP |
| .B Trace file format v1 |
| Each line represents a single I/O action in the following format: |
| .RS |
| .RS |
| .P |
| rw, offset, length |
| .RE |
| .P |
| where `rw=0/1' for read/write, and the `offset' and `length' entries being in bytes. |
| .P |
| This format is not supported in fio versions >= 1.20\-rc3. |
| .RE |
| .TP |
| .B Trace file format v2 |
| The second version of the trace file format was added in fio version 1.17. It |
| allows to access more then one file per trace and has a bigger set of possible |
| file actions. |
| .RS |
| .P |
| The first line of the trace file has to be: |
| .RS |
| .P |
| "fio version 2 iolog" |
| .RE |
| .P |
| Following this can be lines in two different formats, which are described below. |
| .P |
| .B |
| The file management format: |
| .RS |
| filename action |
| .P |
| The `filename' is given as an absolute path. The `action' can be one of these: |
| .RS |
| .TP |
| .B add |
| Add the given `filename' to the trace. |
| .TP |
| .B open |
| Open the file with the given `filename'. The `filename' has to have |
| been added with the \fBadd\fR action before. |
| .TP |
| .B close |
| Close the file with the given `filename'. The file has to have been |
| \fBopen\fRed before. |
| .RE |
| .RE |
| .P |
| .B |
| The file I/O action format: |
| .RS |
| filename action offset length |
| .P |
| The `filename' is given as an absolute path, and has to have been \fBadd\fRed and |
| \fBopen\fRed before it can be used with this format. The `offset' and `length' are |
| given in bytes. The `action' can be one of these: |
| .RS |
| .TP |
| .B wait |
| Wait for `offset' microseconds. Everything below 100 is discarded. |
| The time is relative to the previous `wait' statement. |
| .TP |
| .B read |
| Read `length' bytes beginning from `offset'. |
| .TP |
| .B write |
| Write `length' bytes beginning from `offset'. |
| .TP |
| .B sync |
| \fBfsync\fR\|(2) the file. |
| .TP |
| .B datasync |
| \fBfdatasync\fR\|(2) the file. |
| .TP |
| .B trim |
| Trim the given file from the given `offset' for `length' bytes. |
| .RE |
| .RE |
| .SH I/O REPLAY \- MERGING TRACES |
| Colocation is a common practice used to get the most out of a machine. |
| Knowing which workloads play nicely with each other and which ones don't is |
| a much harder task. While fio can replay workloads concurrently via multiple |
| jobs, it leaves some variability up to the scheduler making results harder to |
| reproduce. Merging is a way to make the order of events consistent. |
| .P |
| Merging is integrated into I/O replay and done when a \fBmerge_blktrace_file\fR |
| is specified. The list of files passed to \fBread_iolog\fR go through the merge |
| process and output a single file stored to the specified file. The output file is |
| passed on as if it were the only file passed to \fBread_iolog\fR. An example would |
| look like: |
| .RS |
| .P |
| $ fio \-\-read_iolog="<file1>:<file2>" \-\-merge_blktrace_file="<output_file>" |
| .RE |
| .P |
| Creating only the merged file can be done by passing the command line argument |
| \fBmerge-blktrace-only\fR. |
| .P |
| Scaling traces can be done to see the relative impact of any particular trace |
| being slowed down or sped up. \fBmerge_blktrace_scalars\fR takes in a colon |
| separated list of percentage scalars. It is index paired with the files passed |
| to \fBread_iolog\fR. |
| .P |
| With scaling, it may be desirable to match the running time of all traces. |
| This can be done with \fBmerge_blktrace_iters\fR. It is index paired with |
| \fBread_iolog\fR just like \fBmerge_blktrace_scalars\fR. |
| .P |
| In an example, given two traces, A and B, each 60s long. If we want to see |
| the impact of trace A issuing IOs twice as fast and repeat trace A over the |
| runtime of trace B, the following can be done: |
| .RS |
| .P |
| $ fio \-\-read_iolog="<trace_a>:"<trace_b>" \-\-merge_blktrace_file"<output_file>" \-\-merge_blktrace_scalars="50:100" \-\-merge_blktrace_iters="2:1" |
| .RE |
| .P |
| This runs trace A at 2x the speed twice for approximately the same runtime as |
| a single run of trace B. |
| .SH CPU IDLENESS PROFILING |
| In some cases, we want to understand CPU overhead in a test. For example, we |
| test patches for the specific goodness of whether they reduce CPU usage. |
| Fio implements a balloon approach to create a thread per CPU that runs at idle |
| priority, meaning that it only runs when nobody else needs the cpu. |
| By measuring the amount of work completed by the thread, idleness of each CPU |
| can be derived accordingly. |
| .P |
| An unit work is defined as touching a full page of unsigned characters. Mean and |
| standard deviation of time to complete an unit work is reported in "unit work" |
| section. Options can be chosen to report detailed percpu idleness or overall |
| system idleness by aggregating percpu stats. |
| .SH VERIFICATION AND TRIGGERS |
| Fio is usually run in one of two ways, when data verification is done. The first |
| is a normal write job of some sort with verify enabled. When the write phase has |
| completed, fio switches to reads and verifies everything it wrote. The second |
| model is running just the write phase, and then later on running the same job |
| (but with reads instead of writes) to repeat the same I/O patterns and verify |
| the contents. Both of these methods depend on the write phase being completed, |
| as fio otherwise has no idea how much data was written. |
| .P |
| With verification triggers, fio supports dumping the current write state to |
| local files. Then a subsequent read verify workload can load this state and know |
| exactly where to stop. This is useful for testing cases where power is cut to a |
| server in a managed fashion, for instance. |
| .P |
| A verification trigger consists of two things: |
| .RS |
| .P |
| 1) Storing the write state of each job. |
| .P |
| 2) Executing a trigger command. |
| .RE |
| .P |
| The write state is relatively small, on the order of hundreds of bytes to single |
| kilobytes. It contains information on the number of completions done, the last X |
| completions, etc. |
| .P |
| A trigger is invoked either through creation ('touch') of a specified file in |
| the system, or through a timeout setting. If fio is run with |
| `\-\-trigger\-file=/tmp/trigger\-file', then it will continually |
| check for the existence of `/tmp/trigger\-file'. When it sees this file, it |
| will fire off the trigger (thus saving state, and executing the trigger |
| command). |
| .P |
| For client/server runs, there's both a local and remote trigger. If fio is |
| running as a server backend, it will send the job states back to the client for |
| safe storage, then execute the remote trigger, if specified. If a local trigger |
| is specified, the server will still send back the write state, but the client |
| will then execute the trigger. |
| .RE |
| .P |
| .B Verification trigger example |
| .RS |
| Let's say we want to run a powercut test on the remote Linux machine 'server'. |
| Our write workload is in `write\-test.fio'. We want to cut power to 'server' at |
| some point during the run, and we'll run this test from the safety or our local |
| machine, 'localbox'. On the server, we'll start the fio backend normally: |
| .RS |
| .P |
| server# fio \-\-server |
| .RE |
| .P |
| and on the client, we'll fire off the workload: |
| .RS |
| .P |
| localbox$ fio \-\-client=server \-\-trigger\-file=/tmp/my\-trigger \-\-trigger\-remote="bash \-c "echo b > /proc/sysrq\-triger"" |
| .RE |
| .P |
| We set `/tmp/my\-trigger' as the trigger file, and we tell fio to execute: |
| .RS |
| .P |
| echo b > /proc/sysrq\-trigger |
| .RE |
| .P |
| on the server once it has received the trigger and sent us the write state. This |
| will work, but it's not really cutting power to the server, it's merely |
| abruptly rebooting it. If we have a remote way of cutting power to the server |
| through IPMI or similar, we could do that through a local trigger command |
| instead. Let's assume we have a script that does IPMI reboot of a given hostname, |
| ipmi\-reboot. On localbox, we could then have run fio with a local trigger |
| instead: |
| .RS |
| .P |
| localbox$ fio \-\-client=server \-\-trigger\-file=/tmp/my\-trigger \-\-trigger="ipmi\-reboot server" |
| .RE |
| .P |
| For this case, fio would wait for the server to send us the write state, then |
| execute `ipmi\-reboot server' when that happened. |
| .RE |
| .P |
| .B Loading verify state |
| .RS |
| To load stored write state, a read verification job file must contain the |
| \fBverify_state_load\fR option. If that is set, fio will load the previously |
| stored state. For a local fio run this is done by loading the files directly, |
| and on a client/server run, the server backend will ask the client to send the |
| files over and load them from there. |
| .RE |
| .SH LOG FILE FORMATS |
| Fio supports a variety of log file formats, for logging latencies, bandwidth, |
| and IOPS. The logs share a common format, which looks like this: |
| .RS |
| .P |
| time (msec), value, data direction, block size (bytes), offset (bytes), |
| command priority |
| .RE |
| .P |
| `Time' for the log entry is always in milliseconds. The `value' logged depends |
| on the type of log, it will be one of the following: |
| .RS |
| .TP |
| .B Latency log |
| Value is latency in nsecs |
| .TP |
| .B Bandwidth log |
| Value is in KiB/sec |
| .TP |
| .B IOPS log |
| Value is IOPS |
| .RE |
| .P |
| `Data direction' is one of the following: |
| .RS |
| .TP |
| .B 0 |
| I/O is a READ |
| .TP |
| .B 1 |
| I/O is a WRITE |
| .TP |
| .B 2 |
| I/O is a TRIM |
| .RE |
| .P |
| The entry's `block size' is always in bytes. The `offset' is the position in bytes |
| from the start of the file for that particular I/O. The logging of the offset can be |
| toggled with \fBlog_offset\fR. |
| .P |
| `Command priority` is 0 for normal priority and 1 for high priority. This is controlled |
| by the ioengine specific \fBcmdprio_percentage\fR. |
| .P |
| Fio defaults to logging every individual I/O but when windowed logging is set |
| through \fBlog_avg_msec\fR, either the average (by default) or the maximum |
| (\fBlog_max_value\fR is set) `value' seen over the specified period of time |
| is recorded. Each `data direction' seen within the window period will aggregate |
| its values in a separate row. Further, when using windowed logging the `block |
| size' and `offset' entries will always contain 0. |
| .SH CLIENT / SERVER |
| Normally fio is invoked as a stand-alone application on the machine where the |
| I/O workload should be generated. However, the backend and frontend of fio can |
| be run separately i.e., the fio server can generate an I/O workload on the "Device |
| Under Test" while being controlled by a client on another machine. |
| .P |
| Start the server on the machine which has access to the storage DUT: |
| .RS |
| .P |
| $ fio \-\-server=args |
| .RE |
| .P |
| where `args' defines what fio listens to. The arguments are of the form |
| `type,hostname' or `IP,port'. `type' is either `ip' (or ip4) for TCP/IP |
| v4, `ip6' for TCP/IP v6, or `sock' for a local unix domain socket. |
| `hostname' is either a hostname or IP address, and `port' is the port to listen |
| to (only valid for TCP/IP, not a local socket). Some examples: |
| .RS |
| .TP |
| 1) \fBfio \-\-server\fR |
| Start a fio server, listening on all interfaces on the default port (8765). |
| .TP |
| 2) \fBfio \-\-server=ip:hostname,4444\fR |
| Start a fio server, listening on IP belonging to hostname and on port 4444. |
| .TP |
| 3) \fBfio \-\-server=ip6:::1,4444\fR |
| Start a fio server, listening on IPv6 localhost ::1 and on port 4444. |
| .TP |
| 4) \fBfio \-\-server=,4444\fR |
| Start a fio server, listening on all interfaces on port 4444. |
| .TP |
| 5) \fBfio \-\-server=1.2.3.4\fR |
| Start a fio server, listening on IP 1.2.3.4 on the default port. |
| .TP |
| 6) \fBfio \-\-server=sock:/tmp/fio.sock\fR |
| Start a fio server, listening on the local socket `/tmp/fio.sock'. |
| .RE |
| .P |
| Once a server is running, a "client" can connect to the fio server with: |
| .RS |
| .P |
| $ fio <local\-args> \-\-client=<server> <remote\-args> <job file(s)> |
| .RE |
| .P |
| where `local\-args' are arguments for the client where it is running, `server' |
| is the connect string, and `remote\-args' and `job file(s)' are sent to the |
| server. The `server' string follows the same format as it does on the server |
| side, to allow IP/hostname/socket and port strings. |
| .P |
| Fio can connect to multiple servers this way: |
| .RS |
| .P |
| $ fio \-\-client=<server1> <job file(s)> \-\-client=<server2> <job file(s)> |
| .RE |
| .P |
| If the job file is located on the fio server, then you can tell the server to |
| load a local file as well. This is done by using \fB\-\-remote\-config\fR: |
| .RS |
| .P |
| $ fio \-\-client=server \-\-remote\-config /path/to/file.fio |
| .RE |
| .P |
| Then fio will open this local (to the server) job file instead of being passed |
| one from the client. |
| .P |
| If you have many servers (example: 100 VMs/containers), you can input a pathname |
| of a file containing host IPs/names as the parameter value for the |
| \fB\-\-client\fR option. For example, here is an example `host.list' |
| file containing 2 hostnames: |
| .RS |
| .P |
| .PD 0 |
| host1.your.dns.domain |
| .P |
| host2.your.dns.domain |
| .PD |
| .RE |
| .P |
| The fio command would then be: |
| .RS |
| .P |
| $ fio \-\-client=host.list <job file(s)> |
| .RE |
| .P |
| In this mode, you cannot input server-specific parameters or job files \-\- all |
| servers receive the same job file. |
| .P |
| In order to let `fio \-\-client' runs use a shared filesystem from multiple |
| hosts, `fio \-\-client' now prepends the IP address of the server to the |
| filename. For example, if fio is using the directory `/mnt/nfs/fio' and is |
| writing filename `fileio.tmp', with a \fB\-\-client\fR `hostfile' |
| containing two hostnames `h1' and `h2' with IP addresses 192.168.10.120 and |
| 192.168.10.121, then fio will create two files: |
| .RS |
| .P |
| .PD 0 |
| /mnt/nfs/fio/192.168.10.120.fileio.tmp |
| .P |
| /mnt/nfs/fio/192.168.10.121.fileio.tmp |
| .PD |
| .RE |
| .P |
| Terse output in client/server mode will differ slightly from what is produced |
| when fio is run in stand-alone mode. See the terse output section for details. |
| .SH AUTHORS |
| .B fio |
| was written by Jens Axboe <axboe@kernel.dk>. |
| .br |
| This man page was written by Aaron Carroll <aaronc@cse.unsw.edu.au> based |
| on documentation by Jens Axboe. |
| .br |
| This man page was rewritten by Tomohiro Kusumi <tkusumi@tuxera.com> based |
| on documentation by Jens Axboe. |
| .SH "REPORTING BUGS" |
| Report bugs to the \fBfio\fR mailing list <fio@vger.kernel.org>. |
| .br |
| See \fBREPORTING\-BUGS\fR. |
| .P |
| \fBREPORTING\-BUGS\fR: \fIhttp://git.kernel.dk/cgit/fio/plain/REPORTING\-BUGS\fR |
| .SH "SEE ALSO" |
| For further documentation see \fBHOWTO\fR and \fBREADME\fR. |
| .br |
| Sample jobfiles are available in the `examples/' directory. |
| .br |
| These are typically located under `/usr/share/doc/fio'. |
| .P |
| \fBHOWTO\fR: \fIhttp://git.kernel.dk/cgit/fio/plain/HOWTO\fR |
| .br |
| \fBREADME\fR: \fIhttp://git.kernel.dk/cgit/fio/plain/README\fR |