From: Neil Brown <neilb@suse.de>
To: "Lucian Șandor" <lucisandor@gmail.com>
Cc: linux-raid@vger.kernel.org
Subject: Re: RAID5 demise or coma? after re-creating with a spare
Date: Sat, 5 Dec 2009 08:12:31 +1100 [thread overview]
Message-ID: <20091205081231.22625302@notabene.brown> (raw)
In-Reply-To: <c775b4470912041146rcff477bj97e86eca5bdb2dfa@mail.gmail.com>
On Fri, 4 Dec 2009 14:46:39 -0500
Lucian Șandor <lucisandor@gmail.com> wrote:
> Hi all,
> There is a problem with my Linux installation, and the drives get
> renamed and reordered all the time. Now, it just happened that the two
> degraded RAID5s won't return to life. The system would not boot, so I
> panicked and deleted: fstab, mdadm.conf, and some of the superblocks.
> Now Linux boots, but RAIDs are, of course, dead. I tried to re-create
> the arrays, but I cannot recall the correct order and my attempts
> failed. I believe that the partitions are OK, because I don't recall
> re-creating without "missing", but surely the superblocks are damaged
> and certanily most of them are zero now.
> Is there a short way to recover the degraded RAIDs without knowing the
> order of drives? I have 6 drives in one (including "missing"), that
> gives 720 permutations. Also, clearing the superblocks is recoverable,
> isn't it?
Yes, 720 permutations. But you can probably write a script
to generate them all ... how good are your programming skills?
Use "--assume-clean" to create the array so that it doesn't
auto-resync. Then "fsck -n" to see of the data is even close
to correct.
And why would you think that erasing the superblocks is a recoverable
operation? It isn't.
NeilBrown
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next prev parent reply other threads:[~2009-12-04 21:12 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-04 19:46 RAID5 demise or coma? after re-creating with a spare Lucian Șandor
2009-12-04 19:53 ` Lucian Șandor
2009-12-04 21:12 ` Neil Brown [this message]
2009-12-06 11:00 ` Lucian Șandor
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