Scott Silva wrote:
Could it be that the bad sectors so far have been in unused areas? Once a drive runs out of sectors to map corrections to, I would really think about replacing it.
This advice is so often repeated by people on lists. This is a pretty normal function of modern hard drives. The drive needs to reallocate the bad sectors. It does not mean that the drive is failing unless there have been a large number of sectors requiring reallocation or it keeps happening often.
Have a look at this to fix them for normal drives without raid: http://smartmontools.sourceforge.net/badblockhowto.html
Linux raid will rewrite the block if it is in the raided part of the disk. You can force a scrub doing this (md0 is the raid device). echo check > /sys/block/md0/md/sync_action Check /proc/mdstat and dmesg for status.
You should be doing this weekly to identify bad blocks, so check your crontab.
Jeremy