projects / thirdparty / mdadm.git / blame
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1 | .\" -*- nroff -*- |
| 2 | .\" Copyright Piergiorgio Sartor and others. | |
| 3 | .\" This program is free software; you can redistribute it and/or modify | |
| 4 | .\" it under the terms of the GNU General Public License as published by | |
| 5 | .\" the Free Software Foundation; either version 2 of the License, or | |
| 6 | .\" (at your option) any later version. | |
| 7 | .\" See file COPYING in distribution for details. | |
| 8 | .TH RAID6CHECK 8 "" v1.0.0 | |
| 9 | .SH NAME | |
| 10 | raid6check \- check MD RAID6 device for errors | |
| 11 | .I aka | |
| 12 | Linux Software RAID | |
| 13 | ||
| 14 | .SH SYNOPSIS | |
| 15 | ||
| 16 | .BI raid6check " <raid6 device> <start stripe> <number of stripes>" | |
| 17 | ||
| 18 | .SH DESCRIPTION | |
| 19 | RAID6 devices in which one single component drive has errors can use | |
| 20 | the double parity in order to find out which component drive. | |
| 21 | The "raid6check" tool checks, for each stripe, the double parity | |
| 22 | consistency, reports mismatches and, if possible, which | |
| 23 | component drive has the mismatch. | |
| 24 | Since it works at stripe level, it can report different drives with | |
| 25 | mismatches at different stripes. | |
| 26 | ||
| 27 | "raid6check" requires a non-degraded RAID6 MD device as first | |
| 28 | parameter, a starting stripe (usually 0) and the number of stripes | |
| 29 | to be checked. | |
| 30 | If this third parameter is also 0, it will check the array up to | |
| 31 | the end. | |
| 32 | ||
| 33 | "raid6check" will start printing information about the RAID6, then | |
| 34 | for each stripe, it will report the parity rotation status. | |
| 35 | In case of parity mismatches, "raid6check" reports, if possible, | |
| 36 | which component drive could be responsible. Otherwise it reports | |
| 37 | that it is not possible to find the component drive. | |
| 38 | ||
| 39 | If the given MD device is not a RAID6, "raid6check" will, of | |
| 40 | course, not continue. | |
| 41 | ||
| 42 | If the RAID6 MD device is degraded, "raid6check" will report | |
| 43 | an error and it will not proceed further. | |
| 44 | ||
| 45 | No write operations are performed on the array or the components. | |
| 46 | Furthermore, the checked array can be online and in use during | |
| 47 | the operation of "raid6check". | |
| 48 | ||
| 49 | .SH EXAMPLES | |
| 50 | ||
| 51 | .B " raid6check /dev/md0 0 0" | |
| 52 | .br | |
| 53 | This will check /dev/md0 from start to end. | |
| 54 | ||
| 55 | .B " raid6check /dev/md3 0 1" | |
| 56 | .br | |
| 57 | This will check the first stripe of /dev/md3. | |
| 58 | ||
| 59 | .B " raid6check /dev/md1 1000 0" | |
| 60 | .br | |
| 61 | This will check /dev/md1 from stripe 1000 up to the end. | |
| 62 | ||
| 63 | .B " raid6check /dev/m127 128 256" | |
| 64 | .br | |
| 65 | This will check 256 stripes of /dev/md127 starting from stripe 128. | |
| 66 | ||
| 67 | .B " raid6check /dev/md0 0 0 | grep -i error > md0_err.log" | |
| 68 | .br | |
| 69 | This will check /dev/md0 completely and create a log file only | |
| 70 | with errors, if any. | |
| 71 | ||
| 72 | .SH FILES | |
| 73 | ||
| 74 | "raid6check" uses directly the component drives as found in /dev. | |
| 75 | Furthermore, the sysfs interface is needed in order to find out | |
| 76 | the RAID6 parameters. | |
| 77 | ||
| 78 | .SH BUGS | |
| 79 | Negative parameters can lead to unexpected results. | |
| 80 | ||
| 81 | It is not clear what will happen if the RAID6 MD device gets | |
| 82 | degraded during the check. | |
| 83 | ||
| 84 | .PP | |
| 85 | The latest version of | |
| 86 | .I raid6check | |
| 87 | should always be available from | |
| 88 | .IP | |
| 89 | .B http://www.kernel.org/pub/linux/utils/raid/mdadm/ | |
| 90 | .PP | |
| 91 | Related man pages: | |
| 92 | .PP | |
| 93 | .IR mdadm (8) | |
| 94 | .IR mdmon (8), | |
| 95 | .IR mdadm.conf (5), | |
| 96 | .IR md (4). |