QNAP disk failure log

[874377.384908] ata7.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
[874377.392102] ata7.00: failed command: FLUSH CACHE EXT
[874377.397198] ata7.00: cmd ea/00:00:00:00:00/00:00:00:00:00/a0 tag 0
[874377.397198]          res 40/00:01:00:4f:c2/00:00:00:00:00/00 Emask 0x4 (timeout)
[874377.410958] ata7.00: status: { DRDY }
[874377.414753] ata7: hard resetting link
[874387.767905] ata7: softreset failed (1st FIS failed)
[874387.772922] ata7: hard resetting link
[874398.128877] ata7: softreset failed (1st FIS failed)
[874398.133885] ata7: hard resetting link
[874408.487873] ata7: softreset failed (1st FIS failed)
[874408.492881] ata7: limiting SATA link speed to 3.0 Gbps
[874408.492886] ata7: hard resetting link
[874418.542875] ata7: softreset failed (1st FIS failed)
[874418.547896] ata7: reset failed, giving up
[874418.552037] ata7.00: disabled
[874418.552046] ata7.00: device reported invalid CHS sector 0
[874418.552078] sd 6:0:0:0: rejecting I/O to offline device
[874418.557418] md: super_written gets error=-5, uptodate=0
[874418.557423] md/raid1:md9: Disk failure on sdc1, disabling device.
[874418.557423] md/raid1:md9: Operation continuing on 3 devices.
[874418.569374] sd 6:0:0:0: rejecting I/O to offline device
[874418.574711] end_request: I/O error, dev sdc, sector 11703256088
[874418.580736] md: super_written gets error=-5, uptodate=0
[874418.580741] md/raid:md1: Disk failure on sdc3, disabling device.
[874418.580741] md/raid:md1: Operation continuing on 3 devices.
[874418.592511] sd 6:0:0:0: rejecting I/O to offline device
[874418.592887] RAID1 conf printout:
[874418.592890]  --- wd:3 rd:32
[874418.592892]  disk 0, wo:0, o:1, dev:sdb1
[874418.592894]  disk 1, wo:0, o:1, dev:sda1
[874418.592896]  disk 2, wo:0, o:1, dev:sdd1
[874418.592897]  disk 3, wo:1, o:0, dev:sdc1
[874418.597877] ata7: EH complete
[874418.597917] ata7.00: detaching (SCSI 6:0:0:0)
[874418.599365] sd 6:0:0:0: [sdc] Synchronizing SCSI cache
[874418.599426] sd 6:0:0:0: [sdc]
[874418.599430] Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK
[874418.599435] sd 6:0:0:0: [sdc] Stopping disk
[874418.599453] sd 6:0:0:0: [sdc] START_STOP FAILED
[874418.599459] sd 6:0:0:0: [sdc]
[874418.599461] Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK
[874418.605889] RAID1 conf printout:
[874418.605895]  --- wd:3 rd:32
[874418.605899]  disk 0, wo:0, o:1, dev:sdb1
[874418.605902]  disk 1, wo:0, o:1, dev:sda1
[874418.605905]  disk 2, wo:0, o:1, dev:sdd1
[874424.984202] md: unbind<sdc1>
[874424.995866] md: export_rdev(sdc1)
[874427.902535] md/raid1:md13: Disk failure on sdc4, disabling device.
[874427.902535] md/raid1:md13: Operation continuing on 3 devices.
[874428.847311] RAID1 conf printout:
[874428.847316]  --- wd:3 rd:32
[874428.847321]  disk 0, wo:0, o:1, dev:sdb4
[874428.847323]  disk 1, wo:0, o:1, dev:sda4
[874428.847326]  disk 2, wo:0, o:1, dev:sdd4
[874428.847329]  disk 3, wo:1, o:0, dev:sdc4
[874428.851854] RAID1 conf printout:
[874428.851859]  --- wd:3 rd:32
[874428.851862]  disk 0, wo:0, o:1, dev:sdb4
[874428.851864]  disk 1, wo:0, o:1, dev:sda4
[874428.851867]  disk 2, wo:0, o:1, dev:sdd4
[874429.450314] md: unbind<sdc4>
[874429.454861] md: export_rdev(sdc4)
[874431.493701] md/raid1:md256: Disk failure on sdc2, disabling device.
[874431.493701] md/raid1:md256: Operation continuing on 2 devices.
[874431.888042] RAID1 conf printout:
[874431.888049]  --- wd:2 rd:2
[874431.888053]  disk 0, wo:0, o:1, dev:sdb2
[874431.888056]  disk 1, wo:0, o:1, dev:sda2
[874431.888312] md: unbind<sdc2>
[874431.893893] md: export_rdev(sdc2)
[874435.368913] md: unbind<sdc3>
[874435.375861] md: export_rdev(sdc3)
[874435.375898] Check proc_name[ahci].
[874435.376199] Check proc_name[ahci].