DMESG:

[82052.800077] mptscsih: ioc2: attempting task abort! (sc=ffff8807d981c900)
[82052.800087] sd 2:0:4:0: [sdu] CDB: ATA command pass through(12)/Blank: a1 08 2e 00 01 00 00 00 00 ec 00 00
[82053.833496] mptbase: ioc2: LogInfo(0x31140000): Originator={PL}, Code={IO Executed}, SubCode(0x0000)
[82053.833911] mptscsih: ioc2: task abort: SUCCESS (sc=ffff8807d981c900)
[82054.333710] mptscsih: ioc2: attempting task abort! (sc=ffff88040a5adf00)
[82054.333720] sd 2:0:4:0: [sdu] CDB: Synchronize Cache(10): 35 00 00 00 00 00 00 00 00 00
[82054.333743] mptscsih: ioc2: task abort: SUCCESS (sc=ffff88040a5adf00)
[82054.345201] end_request: I/O error, dev sdu, sector 976772992
[82054.345212] md: super_written gets error=-5, uptodate=0
[82054.345220] raid5: Disk failure on sdu, disabling device.
[82054.345224] raid5: Operation continuing on 8 devices.
[82054.365553] RAID5 conf printout:
[82054.365560]  --- rd:9 wd:8
[82054.365566]  disk 0, o:1, dev:sdt
[82054.365570]  disk 1, o:0, dev:sdu
[82054.365574]  disk 2, o:1, dev:sdv
[82054.365577]  disk 3, o:1, dev:sdw
[82054.365581]  disk 4, o:1, dev:sdx
[82054.365584]  disk 5, o:1, dev:sdy
[82054.365587]  disk 6, o:1, dev:sdz
[82054.365591]  disk 7, o:1, dev:sdaa
[82054.365594]  disk 8, o:1, dev:sdab
[82054.420068] RAID5 conf printout:
[82054.420076]  --- rd:9 wd:8
[82054.420082]  disk 0, o:1, dev:sdt
[82054.420087]  disk 2, o:1, dev:sdv
[82054.420092]  disk 3, o:1, dev:sdw
[82054.420096]  disk 4, o:1, dev:sdx
[82054.420100]  disk 5, o:1, dev:sdy
[82054.420104]  disk 6, o:1, dev:sdz
[82054.420108]  disk 7, o:1, dev:sdaa
[82054.420113]  disk 8, o:1, dev:sdab
[82054.432967] sd 2:0:4:0: [sdu] Sense Key : Recovered Error [current] [descriptor]
[82054.432982] Descriptor sense data with sense descriptors (in hex):
[82054.432987]         72 01 00 1d 00 00 00 0e 09 0c 00 00 00 fe 00 00
[82054.433006]         00 00 00 00 40 50
[82054.433016] sd 2:0:4:0: [sdu] Add. Sense: ATA pass through information available
[82054.433240] sd 1:0:3:0: [sdl] Sense Key : Recovered Error [current] [descriptor]
[82054.433249] Descriptor sense data with sense descriptors (in hex):
[82054.433253]         72 01 00 1d 00 00 00 0e 09 0c 00 00 00 fe 00 00
[82054.433271]         00 00 00 00 40 50
[82054.433279] sd 1:0:3:0: [sdl] Add. Sense: ATA pass through information available
[82054.434857] sd 2:0:4:0: [sdu] Sense Key : Recovered Error [current] [descriptor]
[82054.434869] Descriptor sense data with sense descriptors (in hex):
[82054.434874]         72 01 00 1d 00 00 00 0e 09 0c 00 00 00 00 00 00
[82054.434891]         00 00 00 00 00 00
[82054.434900] sd 2:0:4:0: [sdu] Add. Sense: ATA pass through information available
[82054.434959] sd 1:0:3:0: [sdl] Sense Key : Recovered Error [current] [descriptor]
[82054.434967] Descriptor sense data with sense descriptors (in hex):
[82054.434972]         72 01 00 1d 00 00 00 0e 09 0c 00 00 00 00 00 00
[82054.434988]         00 00 00 00 00 00
[82054.434997] sd 1:0:3:0: [sdl] Add. Sense: ATA pass through information available

MDSTAT:

:0.mbailey.urizen- cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid0 md1[0] md5[4] md4[3] md3[2] md2[1]
      17093519360 blocks 256k chunks

md4 : active raid6 sdah[5] sdac[0] sdak[8] sdaj[7] sdai[6] sdag[4] sdaf[3] sdae[2] sdad[1]
      3418704128 blocks level 6, 256k chunk, algorithm 2 [9/9] [UUUUUUUUU]

md5 : active raid6 sdar[6] sdan[2] sdal[0] sdat[8] sdas[7] sdaq[5] sdap[4] sdao[3] sdam[1]
      3418704128 blocks level 6, 256k chunk, algorithm 2 [9/9] [UUUUUUUUU]

md1 : active raid6 sde[4] sdf[3] sdb[0] sdj[8] sdi[7] sdh[6] sdg[5] sdd[2] sdc[1]
      3418704128 blocks level 6, 256k chunk, algorithm 2 [9/9] [UUUUUUUUU]

md3 : active raid6 sdu[9](F) sdw[3] sdy[5] sdv[2] sdz[6] sdt[0] sdx[4] sdab[8] sdaa[7]
      3418704128 blocks level 6, 256k chunk, algorithm 2 [9/8] [U_UUUUUUU]

md2 : active raid6 sdr[7] sdq[6] sds[8] sdk[0] sdp[5] sdo[4] sdn[3] sdm[2] sdl[1]
      3418704128 blocks level 6, 256k chunk, algorithm 2 [9/9] [UUUUUUUUU]