Re: replace disk in raid5 without linux noticing?

[Martin Cracauer <cracauer@cons.org>]

Carlos Carvalho wrote on Sat, Apr 22, 2006 at 02:48:23PM -0300: 
> Martin Cracauer (cracauer@cons.org) wrote on 22 April 2006 11:08:
>  >> stop the array
>  >> dd warning disk => new one
>  >> remove warning disk
>  >> assemble the array again with the new disk
>  >> 
>  >> The inconvenience is that you don't have the array during the copy.
>  >
>  >Stopping the array and restarting it as readonly will give you access
>  >to the data while that copy is in progress.
> 
> Yes but then you could just switch it to read-only without stopping.

I believe that would be fine to do the whole operation.  Filesystem
read-only, then md read-only, copy disk, then you need to unmount and
stop the md to restart it with the new disk.

If the final disk change involves a powerdown and putting the new disk
on the physical interface that the old one was on it should be
transparent.

%%

BTW, last time I tested a Linux software RAID-5 by ripping out an
active disk I noticed that while the filesystem stayed up and usable,
a currently ongoing system call would not return and block forever.

Is that a know behaviour?

Martin
-- 
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Martin Cracauer <cracauer@cons.org>   http://www.cons.org/cracauer/
FreeBSD - where you want to go, today.      http://www.freebsd.org/