One of my VM's is locking up with random filesystem errors inside the VM. Looking at the host I see these in the kern log:
[Fri Mar 18 04:00:51 2016] EXT4-fs (loop1): error count since last fsck: 11
[Fri Mar 18 04:00:51 2016] EXT4-fs (loop1): initial error at time 1456211823: ext4_free_blocks:4889
[Fri Mar 18 04:00:51 2016] EXT4-fs (loop1): last error at time 1456219004: ext4_free_blocks:4889
The drive appears to be fine, it is software raid-1 and SMART does not report any errors.
[Fri Mar 18 04:00:51 2016] EXT4-fs (loop1): error count since last fsck: 11
[Fri Mar 18 04:00:51 2016] EXT4-fs (loop1): initial error at time 1456211823: ext4_free_blocks:4889
[Fri Mar 18 04:00:51 2016] EXT4-fs (loop1): last error at time 1456219004: ext4_free_blocks:4889
The drive appears to be fine, it is software raid-1 and SMART does not report any errors.