| .\" -*- nroff -*- |
| .\" Copyright Piergiorgio Sartor and others. |
| .\" This program is free software; you can redistribute it and/or modify |
| .\" it under the terms of the GNU General Public License as published by |
| .\" the Free Software Foundation; either version 2 of the License, or |
| .\" (at your option) any later version. |
| .\" See file COPYING in distribution for details. |
| .TH RAID6CHECK 8 "" v1.0.0 |
| .SH NAME |
| raid6check \- check MD RAID6 device for errors |
| .I aka |
| Linux Software RAID |
| |
| .SH SYNOPSIS |
| |
| .BI raid6check " <raid6 device> <start stripe> <number of stripes>" |
| |
| .SH DESCRIPTION |
| RAID6 devices in which one single component drive has errors can use |
| the double parity in order to find out which component drive. |
| The "raid6check" tool checks, for each stripe, the double parity |
| consistency, reports mismatches and, if possible, which |
| component drive has the mismatch. |
| Since it works at stripe level, it can report different drives with |
| mismatches at different stripes. |
| |
| "raid6check" requires a non-degraded RAID6 MD device as first |
| parameter, a starting stripe (usually 0) and the number of stripes |
| to be checked. |
| If this third parameter is also 0, it will check the array up to |
| the end. |
| |
| "raid6check" will start printing information about the RAID6, then |
| for each stripe, it will report the parity rotation status. |
| In case of parity mismatches, "raid6check" reports, if possible, |
| which component drive could be responsible. Otherwise it reports |
| that it is not possible to find the component drive. |
| |
| If the given MD device is not a RAID6, "raid6check" will, of |
| course, not continue. |
| |
| If the RAID6 MD device is degraded, "raid6check" will report |
| an error and it will not proceed further. |
| |
| No write operations are performed on the array or the components. |
| Furthermore, the checked array can be online and in use during |
| the operation of "raid6check". |
| |
| .SH EXAMPLES |
| |
| .B " raid6check /dev/md0 0 0" |
| .br |
| This will check /dev/md0 from start to end. |
| |
| .B " raid6check /dev/md3 0 1" |
| .br |
| This will check the first stripe of /dev/md3. |
| |
| .B " raid6check /dev/md1 1000 0" |
| .br |
| This will check /dev/md1 from stripe 1000 up to the end. |
| |
| .B " raid6check /dev/m127 128 256" |
| .br |
| This will check 256 stripes of /dev/md127 starting from stripe 128. |
| |
| .B " raid6check /dev/md0 0 0 | grep -i error > md0_err.log" |
| .br |
| This will check /dev/md0 completely and create a log file only |
| with errors, if any. |
| |
| .SH FILES |
| |
| "raid6check" uses directly the component drives as found in /dev. |
| Furthermore, the sysfs interface is needed in order to find out |
| the RAID6 parameters. |
| |
| .SH BUGS |
| Negative parameters can lead to unexpected results. |
| |
| It is not clear what will happen if the RAID6 MD device gets |
| degraded during the check. |
| |
| .PP |
| The latest version of |
| .I raid6check |
| should always be available from |
| .IP |
| .B https://www.kernel.org/pub/linux/utils/raid/mdadm/ |
| .PP |
| Related man pages: |
| .PP |
| .IR mdadm (8) |
| .IR mdmon (8), |
| .IR mdadm.conf (5), |
| .IR md (4). |