From mboxrd@z Thu Jan  1 00:00:00 1970
From: =?UTF-8?Q?Patrik_Dahlstr=C3=B6m?= <risca@powerlamerz.org>
Subject: Re: Recover array after I panicked
Date: Tue, 25 Apr 2017 12:51:59 +0200
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To: Andreas Klauer <Andreas.Klauer@metamorpher.de>
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2017-04-25 12:40 GMT+02:00, Patrik Dahlstr=C3=B6m <risca@powerlamerz.org>:
> 2017-04-25 11:01 GMT+02:00, Andreas Klauer <Andreas.Klauer@metamorpher.de=
>:
>> On Tue, Apr 25, 2017 at 10:44:15AM +0200, Patrik Dahlstr=C3=B6m wrote:
>> You found multiple filesystem headers, do you know the UUID it should
>> have so you're not working with some old remnant?
> The file systems looks correct:
> $ grep storage /etc/fstab
> # commented out during recovery
> #UUID=3D345ec7b8-b523-45d3-8c2e-35cda1ab62c1 /storage        ext4
> errors=3Dremount-ro 0       1
> $ file -s /dev/md0
> /dev/md0: Linux rev 1.0 ext4 filesystem data,
> UUID=3D345ec7b8-b523-45d3-8c2e-35cda1ab62c1 (extents) (64bit) (large
> files) (huge files)
> $ file -s /dev/md1
> /dev/md1: Linux rev 1.0 ext4 filesystem data,
> UUID=3D345ec7b8-b523-45d3-8c2e-35cda1ab62c1 (extents) (64bit) (large
> files) (huge files)
This actually got me thinking. During my destructive recovery
attempts, I would either don't specify a --data-offset or use
--data-offset=3D128M. Since the correct offsets are less than 128M
(123,5 MB actually), that data would be untouched in case a
reshape/rebuild was triggered by my attempts. That must explain why
the first 4 chunks of /dev/md{0,1} were identical when using correct
offset, right?