| btrfs-device(8) |
| =============== |
| |
| NAME |
| ---- |
| btrfs-device - control btrfs devices |
| |
| SYNOPSIS |
| -------- |
| *btrfs device* <subcommand> <args> |
| |
| DESCRIPTION |
| ----------- |
| *btrfs device* is used to control the btrfs devices, since btrfs can be used |
| across several devices, *btrfs device* is used for multiple device management. |
| |
| DEVICE MANAGEMENT |
| ----------------- |
| Btrfs filesystem is capable to manage multiple devices. |
| |
| Btrfs filesystem uses different profiles to manage different RAID level, and |
| use balance to rebuild chunks, also devices can be added/removed/replace |
| online. |
| |
| Profile:: |
| Btrfs filesystem uses data/metadata profiles to manage allocation/duplication |
| mechanism. + |
| Profiles like RAID level can be assigned to data and metadata separately. |
| + |
| See `mkfs.btrfs`(8) for more details. |
| |
| RAID level:: |
| Btrfs filesystem supports most of the standard RAID level: 0/1/5/6/10. + |
| RAID levels can be assigned at mkfs time or online. |
| + |
| See `mkfs.btrfs`(8) for mkfs time RAID level assign and `btrfs-balance`(8) for |
| online RAID level assign. |
| + |
| NOTE: Since btrfs is under heavy development especially the RAID5/6 support, |
| it is *highly* recommended to read the follow btrfs wiki page to get more |
| updated details on RAID5/6: + |
| https://btrfs.wiki.kernel.org/index.php/RAID56 |
| |
| Balance:: |
| `btrfs-balance`(8) subcommand can be used to balance or rebuild chunks to the |
| desired profile. |
| + |
| Due to the fact that balance can rebuild/recovery chunks according to its RAID |
| duplication if possible, so when using RAID1/5/6/10 with some devices failed |
| and you just added a new device to btrfs using `btrfs-device`(8), you should |
| run `btrfs-balance`(8) to rebuild the chunks. |
| + |
| See `btrfs-balance`(8) for more details. |
| |
| Device add/remove/replace:: |
| Device can be added/removed using `btrfs-replace`(8) subcommand and replaced |
| using `btrfs-replace`(8). |
| + |
| When device is removed or replaced, btrfs will do the chunk rebuild if needed. |
| + |
| See `btrfs-replace`(8) and this man page for more details. |
| |
| SUBCOMMAND |
| ---------- |
| *add* [-Kf] <dev> [<dev>...] <path>:: |
| Add device(s) to the filesystem identified by <path>. |
| + |
| If applicable, a whole device discard (TRIM) operation is performed. |
| + |
| `Options` |
| + |
| -K|--nodiscard:::: |
| do not perform discard by default |
| -f|--force:::: |
| force overwrite of existing filesystem on the given disk(s) |
| |
| *delete* <dev> [<dev>...] <path>:: |
| Remove device(s) from a filesystem identified by <path>. |
| |
| *ready* <device>:: |
| Check device to see if it has all of it's devices in cache for mounting. |
| |
| *scan* [(--all-devices|-d)|<device> [<device>...]]:: |
| Scan devices for a btrfs filesystem. |
| + |
| If one or more devices are passed, these are scanned for a btrfs filesystem. |
| If no devices are passed, btrfs uses block devices containing btrfs |
| filesystem as listed by blkid. |
| Finally, if '--all-devices' or '-d' is passed, all the devices under /dev are |
| scanned. |
| |
| *stats* [-z] <path>|<device>:: |
| Read and print the device IO stats for all devices of the filesystem |
| identified by <path> or for a single <device>. |
| + |
| `Options` |
| + |
| -z:::: |
| Reset stats to zero after reading them. |
| |
| *usage* [options] <path> [<path>...]:: |
| Show detailed information about internal allocations in devices. |
| + |
| `Options` |
| + |
| -b|--raw:::: |
| raw numbers in bytes, without the 'B' suffix |
| -h|--human-readable:::: |
| print human friendly numbers, base 1024, this is the default |
| -H:::: |
| print human friendly numbers, base 1000 |
| --iec:::: |
| select the 1024 base for the following options, according to the IEC standard |
| --si:::: |
| select the 1000 base for the following options, according to the SI standard |
| -k|--kbytes:::: |
| show sizes in KiB, or kB with --si |
| -m|--mbytes:::: |
| show sizes in MiB, or MB with --si |
| -g|--gbytes:::: |
| show sizes in GiB, or GB with --si |
| -t|--tbytes:::: |
| show sizes in TiB, or TB with --si |
| |
| If conflicting options are passed, the last one takes precedence. |
| |
| EXIT STATUS |
| ----------- |
| *btrfs device* returns a zero exit status if it succeeds. Non zero is |
| returned in case of failure. |
| |
| AVAILABILITY |
| ------------ |
| *btrfs* is part of btrfs-progs. |
| Please refer to the btrfs wiki http://btrfs.wiki.kernel.org for |
| further details. |
| |
| SEE ALSO |
| -------- |
| `mkfs.btrfs`(8), |
| `btrfs-replace`(8), |
| `btrfs-balance`(8) |
