Craig Ringer wrote:
> [for SATA disks]: does smartctl from the smartmontools package indicate
> anything interesting about the disk(s)? (Ignore the "health status",
> it's a foul lie, and rely on the error log plus the vendor attributes:
> reallocated sector count, pending sector, uncorrectable sector count,
> etc).
>
and, if you're doing RAID with desktop grade disks, its quite possible
for the drive to spontaneously decide a sector error requires a data
relocation but not have the 'good' data to relocate, and not return an
error code in time for the RAID controller or host md-raid to do
anything about it. this results in a very sneaky sort of data
corruption which goes undetected until some time later.
this is the primary reason to use the premium "ES" grade SATA drives
rather than the cheaper desktop stuff in a raid, they return sector
errors in a timely fashion rather than retrying for many minutes in the
background.