アレイ新調してからちょうど1年。1台壊れた。

[misumi 19:54:15 /var/www/epgrec]% cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] 
md1 : active raid5 sdb[0] sdc[3](F) sdd[1]
      3907025920 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/2] [UU_]
      
unused devices: <none>


[837940.960034] ata5.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
[837940.960097] ata5.00: failed command: FLUSH CACHE EXT
[837940.960136] ata5.00: cmd ea/00:00:00:00:00/00:00:00:00:00/a0 tag 0
[837940.960136]          res 40/00:01:00:00:00/00:00:00:00:00/40 Emask 0x4 (timeout)
[837940.960222] ata5.00: status: { DRDY }
[837940.960251] ata5: hard resetting link
[837946.320040] ata5: link is slow to respond, please be patient (ready=0)
[837950.972026] ata5: COMRESET failed (errno=-16)
[837950.972069] ata5: hard resetting link
[837956.332017] ata5: link is slow to respond, please be patient (ready=0)
[837960.980021] ata5: COMRESET failed (errno=-16)
[837960.980061] ata5: hard resetting link
[837966.340017] ata5: link is slow to respond, please be patient (ready=0)
[837996.024043] ata5: COMRESET failed (errno=-16)
[837996.024087] ata5: limiting SATA link speed to 1.5 Gbps
[837996.024091] ata5: hard resetting link
[838001.048037] ata5: COMRESET failed (errno=-16)
[838001.048076] ata5: reset failed, giving up
[838001.048107] ata5.00: disabled
[838001.048112] ata5.00: device reported invalid CHS sector 0
[838001.048137] ata5: EH complete
[838001.050938] sd 4:0:0:0: [sdc] Unhandled error code
[838001.050945] sd 4:0:0:0: [sdc]  
[838001.050948] Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK
[838001.050950] sd 4:0:0:0: [sdc] CDB: 
[838001.050952] Write(10): 2a 00 1f 22 20 00 00 04 00 00
[838001.050962] end_request: I/O error, dev sdc, sector 522330112
[838001.068053] sd 4:0:0:0: [sdc] Unhandled error code
[838001.068057] sd 4:0:0:0: [sdc]  
[838001.068059] Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK
[838001.068062] sd 4:0:0:0: [sdc] CDB: 
[838001.068063] Write(10): 2a 00 1f 22 24 00 00 00 08 00
[838001.068073] end_request: I/O error, dev sdc, sector 522331136
[838001.068171] md/raid:md1: Disk failure on sdc, disabling device.
[838001.068171] md/raid:md1: Operation continuing on 2 devices.
[838001.537620] RAID conf printout:
[838001.537625]  --- level:5 rd:3 wd:2
[838001.537628]  disk 0, o:1, dev:sdb
[838001.537631]  disk 1, o:1, dev:sdd
[838001.537634]  disk 2, o:0, dev:sdc
[838001.537663] RAID conf printout:
[838001.537666]  --- level:5 rd:3 wd:2
[838001.537669]  disk 0, o:1, dev:sdb
[838001.537672]  disk 1, o:1, dev:sdd


[misumi 20:22:48 /var/www/epgrec]% ls -l /dev/disk/by-id
合計 0
(snip)
lrwxrwxrwx 1 root root  9  1月 14 20:59 ata-ST2000DL003-9VT166_6YD1JFRA -> ../../sdd
lrwxrwxrwx 1 root root  9  1月 14 20:59 ata-ST2000DM001-9YN164_W2F03251 -> ../../sdc
lrwxrwxrwx 1 root root  9  1月 14 20:59 ata-WDC_WD20EARX-00PASB0_WD-WCAZAD197668 -> ../../sdb

壊れたのはST2000DM001らしい。
WD20EZRX \7,480と交換。