I have a lightly used spinning metal drive (internal) with some VMs on it. I'm running into IO errors while running a VM and upon closer examination I have found a virtual disk file that is reporting an IO error when I try to read it.

The partition is mounted with errors=remount, but it hasn't remounted, indicating (as far as I know) that the filesystem is intact.

Additionally, running a full nondestructive read-write sector scan with fsck has not yielded any bad sectors. Nonetheless, the error remains.

dmesg has this to report about the device (/dev/sdb1) (repeated every few seconds):

[9957544.402127] sas: sas_ata_task_done: SAS error 2
[9957544.402137] sd 2:0:1:0: [sdb] command ffff8801046aec00 timed out
[9957544.402161] sas: Enter sas_scsi_recover_host busy: 1 failed: 1
[9957544.402166] sas: ata8: end_device-2:1: cmd error handler
[9957544.402180] sas: ata7: end_device-2:0: dev error handler
[9957544.402182] sas: ata8: end_device-2:1: dev error handler
[9957544.402188] ata8.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6
[9957544.402190] sas: ata9: end_device-2:2: dev error handler
[9957544.402194] ata8.00: failed command: READ DMA EXT
[9957544.402202] ata8.00: cmd 25/00:08:f0:5f:a1/00:00:4e:00:00/e0 tag 22 dma 4096 in
[9957544.402202]          res 01/04:00:af:6d:70/00:00:74:00:00/e0 Emask 0x3 (HSM violation)
[9957544.402206] ata8.00: status: { ERR }
[9957544.402208] ata8.00: error: { ABRT }
[9957544.402211] ata8: hard resetting link
[9957544.646553] ata8.00: configured for UDMA/33
[9957544.646565] ata8: EH complete
[9957544.646587] sas: --- Exit sas_scsi_recover_host: busy: 0 failed: 0 tries: 1

The data isn't important, and I've done recovery before. This question isn't about getting it back.

I suspect the underlying problem is a bad sector. Why aren't the tools detecting it though? Assuming I was to take the unwise step of continuing to use this device, what tools would work better in diagnosing its problems?

  • Update, for some reason fsck doesn't seem to have reported any errors as it was going, but it does appear to have updated the badblocks file. Weird. I'll leave the question open in case anyone has great suggestions though. – Wug Jan 12 '16 at 22:34

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