Disk Failure Detected...

Just had the same problem with Ultra4 Plus.

Also running all OSX in the house. The NAS has been up for weeks now. I've copied all my media on there. "today" was the 1st time I've really had a chance to use it. Besides copying several multi-gig isos around everything seemed to be ok. I enabled ReadyNAS backup today and kicked off a backup. It was about 70gig into a 250gig backup and I got a failure email from disk3.

I have not done any of the steps yet in this thread, but something weird going on and I specifically bought off the HCL having had issues with NV/NV+ and WD EARS drives awhile go.

from DMESG:

ata5.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
ata5.00: failed command: FLUSH CACHE EXT
ata5.00: cmd ea/00:00:00:00:00/00:00:00:00:00/a0 tag 0
res 40/00:01:00:4f:c2/00:00:00:00:00/00 Emask 0x4 (timeout)
ata5.00: status: { DRDY }
ata5: hard resetting link
ata5: link is slow to respond, please be patient (ready=0)
ata5: COMRESET failed (errno=-16)
ata5: hard resetting link
ata5: link is slow to respond, please be patient (ready=0)
ata5: COMRESET failed (errno=-16)
ata5: hard resetting link
ata5: link is slow to respond, please be patient (ready=0)
ata5: COMRESET failed (errno=-16)
ata5: limiting SATA link speed to 1.5 Gbps
ata5: hard resetting link
ata5: COMRESET failed (errno=-16)
ata5: reset failed, giving up
ata5.00: disabled
ata5.00: device reported invalid CHS sector 0
ata5: EH complete
sd 4:0:0:0: [sdc] Unhandled error code
sd 4:0:0:0: [sdc] Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK
sd 4:0:0:0: [sdc] CDB: Read(10): 28 00 a9 e8 08 00 00 00 08 00
end_request: I/O error, dev sdc, sector 2850555904
sd 4:0:0:0: [sdc] Unhandled error code
sd 4:0:0:0: [sdc] Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK
sd 4:0:0:0: [sdc] CDB: Read(10): 28 00 00 12 89 80 00 00 08 00
end_request: I/O error, dev sdc, sector 1214848
md/raid1:md0: sdc1: rescheduling sector 1212736
sd 4:0:0:0: [sdc] Unhandled error code
sd 4:0:0:0: [sdc] Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK
sd 4:0:0:0: [sdc] CDB: Write(10): 2a 00 00 90 00 50 00 00 02 00
end_request: I/O error, dev sdc, sector 9437264
end_request: I/O error, dev sdc, sector 9437264
md: super_written gets error=-5, uptodate=0
md/raid:md2: Disk failure on sdc5, disabling device.
<1>md/raid:md2: Operation continuing on 3 devices.
sd 4:0:0:0: [sdc] Unhandled error code
sd 4:0:0:0: [sdc] Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK
sd 4:0:0:0: [sdc] CDB: Write(10): 2a 00 00 00 00 48 00 00 02 00
end_request: I/O error, dev sdc, sector 72
end_request: I/O error, dev sdc, sector 72
md: super_written gets error=-5, uptodate=0
md/raid1:md0: Disk failure on sdc1, disabling device.
<1>md/raid1:md0: Operation continuing on 3 devices.
RAID conf printout:
--- level:5 rd:4 wd:3
disk 0, o:1, dev:sda5
disk 1, o:1, dev:sdb5
disk 2, o:0, dev:sdc5
disk 3, o:1, dev:sdd5
RAID conf printout:
--- level:5 rd:4 wd:3
disk 0, o:1, dev:sda5
disk 1, o:1, dev:sdb5
disk 3, o:1, dev:sdd5
RAID1 conf printout:
--- wd:3 rd:4
disk 0, wo:0, o:1, dev:sda1
disk 1, wo:0, o:1, dev:sdb1
disk 2, wo:1, o:0, dev:sdc1
disk 3, wo:0, o:1, dev:sdd1
RAID1 conf printout:
--- wd:3 rd:4
disk 0, wo:0, o:1, dev:sda1
disk 1, wo:0, o:1, dev:sdb1
disk 3, wo:0, o:1, dev:sdd1
md/raid1:md0: redirecting sector 1212736 to other mirror: sdb1

This sux :( It's not cheap to put this stuff together.