On Thu Jul 23, 2015 at 06:07:34PM -0400, John Bridges wrote:
> I have had a problem with mismatch_cnt being huge (well over 500000) on a raid6
>
> /dev/md2:
> Version : 1.0
> Creation Time : Mon Oct 15 20:55:58 2012
> Raid Level : raid6
> Array Size : 35163174912 (33534.22 GiB 36007.09 GB)
> Used Dev Size : 2930264576 (2794.52 GiB 3000.59 GB)
> Raid Devices : 14
> Total Devices : 15
> Persistence : Superblock is persistent
>
> Intent Bitmap : Internal
>
> Update Time : Wed Jul 22 13:04:39 2015
> State : active
> Active Devices : 14
> Working Devices : 15
> Failed Devices : 0
> Spare Devices : 1
>
> Layout : left-symmetric
> Chunk Size : 512K
>
> Name : monster:2 (local to host monster)
> UUID : c9f7456d:39b575fd:5d8e3791:54bffeae
> Events : 459283
>
> Number Major Minor RaidDevice State
> 19 65 129 0 active sync /dev/sdy1
> 1 65 145 1 active sync /dev/sdz1
> 17 65 17 2 active sync /dev/sdr1
> 12 8 193 3 active sync /dev/sdm1
> 8 65 1 4 active sync /dev/sdq1
> 5 65 65 5 active sync /dev/sdu1
> 6 65 81 6 active sync /dev/sdv1
> 7 65 97 7 active sync /dev/sdw1
> 16 8 225 8 active sync /dev/sdo1
> 18 8 209 9 active sync /dev/sdn1
> 15 8 241 10 active sync /dev/sdp1
> 14 65 113 11 active sync /dev/sdx1
> 13 65 177 12 active sync /dev/sdab1
> 20 65 161 13 active sync /dev/sdaa1
>
> 21 8 177 - spare /dev/sdl1
>
>
> mdadm - v3.2.5 - 18th May 2012
>
>
> sync_action check did not fix it.
> I tried sync_action repair, still a huge number.
> Then I ran raid6check (built from latest mdadm source), took over a week to run.
> Found no errors, I was expecting a flaky drive since mismatch_cnt was so huge.
> raid6check does not update mismatch_cnt, so I did a sync_action check
> which finally zeroed the mismatch_cnt.
> I don't know if the newer raid6check fixed it or the repair?
>
> If mismatch_cnt is non zero on a raid6, do I need to do a repair and
> then a check? I thought repair would update mismatch_cnt.
>
>
> Does not inspire confidence.
>
Repair updates mismatch_cnt with the number of mismatches repaired, so
at the end this should equal the number reported by check. I would
always recommend re-running the check after a repair anyway.
That number of mismatches would suggest a major issue with your array
though. I would suggest checking SMART statistics and running full SMART
tests on all member disks.
Cheers,
Robin
--
___
( ' } | Robin Hill <robin@xxxxxxxxxxxxxxx> |
/ / ) | Little Jim says .... |
// !! | "He fallen in de water !!" |
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