Re: recovering a raid conf

["Steven M. Bellovin" <smb%cs.columbia.edu@localhost>]

On Sun, 16 Aug 2009 17:58:03 -0400
Izaac <izaac%setec.org@localhost> wrote:

> On Sun, Aug 16, 2009 at 11:23:02AM -0400, Steven M. Bellovin wrote:
> > I did a rather stupid thing when building a raid-based system: I did
> > 
> >     raidctl -A no raid0
> > 
> > then shut down.  Now, when I try to boot it, it tells me that it
> > knows nothing of raid0.  I have a raid0.conf file -- but on the raid
> > partition...
> > 
> > Is there any easy way to recover it?  A lot of work went into
> > building that disk...
> 
> Fastest:
> It's easier to just rebuild the raid0.conf from scratch.  Boot off an
> install CD and take a S.W.A.G. at your prior configuration.  Use
> 'raidctl -c' (and NOT 'raidctl -C'!!!) with your replacement conf
> file. If correct, it will pop straight up.  If it's not, no harm and
> no foul.

That's what I did.  Fortunately, I'd followed the instructions in the
wiki on RAID installs, and had just copied down those numbers.

Thanks.
> 
> Correctest:
> Alternatively, grep through each of the raw disks for '^START' and
> hope for the best:
> 
>       for x in /dev/rwd0a /dev/rwd1a ... /dev/rwdxa
>       do
>               echo -n "$x ... "
>               grep -a -40 '^START ' $x >> /tmp/crossed-fingers
>               echo DONE
>       done
> 

Hmm...

                --Steve Bellovin, http://www.cs.columbia.edu/~smb