During a parity check, I noticed several times when the speed of the check dipped quite low (< 100 kbps).  Looking at the syslog, I see many of the following types of errors:

 

ata5.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
ata5.00: failed command: READ DMA EXT
ata5.00: cmd 25/00:18:d8:19:27/00:03:74:00:00/e0 tag 0 dma 405504 in
         res 40/00:c7:1f:1a:27/00:02:74:00:00/e0 Emask 0x4 (timeout)
ata5.00: status: { DRDY }
ata5: hard resetting link
ata5: SATA link up 1.5 Gbps (SStatus 113 SControl 310)
ata5.00: configured for UDMA/33
ata5: EH complete

 

ata5.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0
ata5.00: irq_stat 0x48000000
ata5.00: failed command: READ DMA EXT
ata5.00: cmd 25/00:00:c8:4d:8d/00:04:5c:00:00/e0 tag 0 dma 524288 in
         res 51/40:ef:d2:4e:8d/00:02:5c:00:00/e0 Emask 0x9 (media error)
ata5.00: status: { DRDY ERR }
ata5.00: error: { UNC }
ata5.00: configured for UDMA/133
ata5: EH complete

 

handle_stripe read error: 1948720832/8, count: 1
md: disk10 read error

 

I've attached the whole syslog in case I've missed anything.  My understanding is that these errors point to a drive failure, but I wanted to check here to see if there might be other causes or if the drive might be recoverable.  The system is powered off right now, and I'm hesitant to boot it up without a better understanding of what kind of problem the array is experiencing.  Would the safest approach be to simply replace the drive?  Any advice on how to proceed would be appreciated.

syslog.zip

Post a SMART report for disk10.

Here are the smart reports (one from before a short self-test and one from after).  I'm guessing the results of second report mean the drive is no longer trustworthy.  Unfortunately, it's out of warranty, so I want to be sure before I replace it.

smart.zip

The drive is experiencing read failures. The Current_Pending_Sector RAW_VALUE must be zero for the array to operate correctly. Replace with a spare and run pre-clear on the drive. Observe the Current_Pending_Sector RAW_VALUE after pre-clear has completed.

Thanks. I've ordered a replacement drive.