From: Phil Turmel <philip@turmel.org>
To: Daniel Jones <dj@iowni.com>
Cc: Wols Lists <antlists@youngman.org.uk>, linux-raid@vger.kernel.org
Subject: Re: Requesting assistance recovering RAID-5 array
Date: Wed, 1 Apr 2020 14:32:18 -0400 [thread overview]
Message-ID: <bb554b86-3dc0-8cb2-c279-f8841742195c@turmel.org> (raw)
In-Reply-To: <CAB00BMhU76rjvQv9v-HxM8Harc9ssLBANWfPsW9abbSRNgwoUQ@mail.gmail.com>
Hi Daniel,
On 4/1/20 2:07 PM, Daniel Jones wrote:
> Hi Phil,
>
> So far so good.
Yes.
> # mdadm --manage /dev/md0 --add /dev/mapper/sdb1
> mdadm: added /dev/mapper/sdb1
Don't do this. Overlays can't really handle the amount of data that
would be involved, and you definitely don't want to rebuild yet.
> 4: Summary
>
> The drives have had physical partitions written.
> I think I've found the correct offset and device order to use --create
> to restore the array to the degraded state it was in before the
> superblocks were overwritten.
Yes.
> I'm not sure why the --add doesn't work.
Don't do the --add operation until you've copied anything critical in
the array to external backups (while running with 3 of 4). The reason
is that any not-yet-discovered URE on those three will certainly crash
the array during rebuild. It could still crash copying critical stuff,
but you can repeatedly --assemble --force to keep going with the next
items to backup.
Only when you've backed up everything possible do you --add the fourth
drive back into the array.
> Thanks so much for your help this far.
You're welcome.
> Regards,
> DJ
Phil
next prev parent reply other threads:[~2020-04-01 18:32 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-31 0:04 Requesting assistance recovering RAID-5 array Daniel Jones
2020-03-31 0:24 ` antlists
2020-03-31 0:51 ` Daniel Jones
2020-03-31 1:27 ` crowston.name
2020-03-31 1:50 ` Phil Turmel
2020-03-31 1:48 ` Phil Turmel
2020-03-31 2:09 ` Daniel Jones
2020-03-31 12:00 ` Phil Turmel
2020-03-31 13:36 ` Daniel Jones
2020-04-01 3:39 ` Daniel Jones
2020-04-01 4:45 ` Phil Turmel
2020-04-01 6:03 ` Daniel Jones
2020-04-01 12:15 ` Wols Lists
2020-04-01 12:55 ` Phil Turmel
2020-04-01 15:21 ` Daniel Jones
2020-04-01 15:38 ` Phil Turmel
2020-04-01 15:39 ` Phil Turmel
2020-04-01 18:07 ` Daniel Jones
2020-04-01 18:32 ` Phil Turmel [this message]
2020-04-03 18:29 ` Daniel Jones
2020-04-03 18:34 ` Phil Turmel
2020-04-03 18:42 ` Daniel Jones
2020-04-03 18:43 ` Phil Turmel
2020-04-03 20:13 ` Adam Goryachev
2020-04-03 20:14 ` Phil Turmel
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