Re: Disk in a raid array

[David Wright <deblis@lionunicorn.co.uk>]

Quoting James Allsopp (jamesaallsopp@googlemail.com):
> Hi,
> I've got home mounted on a LVM partition over two RAID 1 arrays. Unfortunately
> one of the disks in the second array has dropped out. I can still fdisk -l it,
> but when I ran dd if=/dev/sdd1 of=/dev/null it got about 132M through a 2Tb
> drive before crashing out. This doesn't bode well.
> 
> I can't really afford a new drive, but was wondering if I should just reformat,
> try and check it for errors and then try and add it back to the array? I was
> hoping that doing that might allow it to exclude any bad blocks and get me
> something working for a while whilst I save up.

When I've hit this problem, I'm afraid my solution has always involved
another disk. By using dd with the count, seek and skip parameters, I
made a copy of the partition with a zeroed section where the
unreadable sectors were. I then just ran fsck on the copy and let it
sort out what it could. (I eventually stuck the old drive in a caddy
with a dummy partition hiding the broken section and used it as a
scratch disk for moving videos around.)

Cheers,
David.