[Discuss] unreadable sector

[feenberg at nber.org (Daniel Feenberg)]

On Sat, 12 Oct 2013, Jerry Feldman wrote:

> I've brought this up before. One of the drives in my RAID reports an
> unreadable sector. I'm not worried about thisas this otherwise seems to
> be a serviceable driveand I take frequent backups. One question I might
> have is would I be better served by removing this from the RAID pair,
> and run a full destructive bad block scan 'badblocks -wsv /dev/sda | tee
> <some log file>'

Note that the Linux software RAID 1 or 5 won't be able to resilver the 
other drive if the remaining "good" drive has a bad block. The resilvering 
process will fail at the bad sector, mark the drive with the bad sector 
failed, and not continue, even though the bad sector is not in use. The 
resilvering program doesn't know about files. You can still recover your 
data with file copies, but resilvering will fail.

dan feenberg