Markus W Kilbinger writes:
> Hi!
> 
> After simulating (raidctl -F) a disk failure of a 4 disk raid5 (3 + 1
> spare), the spare disk got in 'used_spare' state and the whole raid
> was still usable under the 'reconstructing' phase. Fine!
> 
> But what's the smooth way (== the system is still usable during that
> time) back? 'raidctl -B' did the job, but blocks the whole system for
> the complete copyback time! 

It blocks the filesystem(s) on the RAID set...  Unfortunatly, this is a 
limitation of the copyback code.

> Trying it with 'raidctl -R ...', while the
> spare is in use, reconstructed the formerly failed disk smoothly, but
> left the spare disk in 'used_spare' state.

Hmm!! It really shouldn't be letting you do a 'raidctl -R' after you've 
already reconstructed to a spare... smells like a bug.. 

> If this blocking is not avoidable you have to really care about _when_
> doing it with a production server! ;-)
> 
> Markus.

Later...

Greg Oster