From: Andreas Klauer <Andreas.Klauer@metamorpher.de>
To: Patrick Tschackert <Killing-Time@gmx.de>
Cc: linux-raid@vger.kernel.org
Subject: Re: problems with dm-raid 6
Date: Sun, 20 Mar 2016 23:37:27 +0100 [thread overview]
Message-ID: <20160320223727.GA29895@EIS> (raw)
In-Reply-To: <trinity-dd5fc296-8c28-4b99-85de-889a495e6956-1458510296940@3capp-gmx-bs09>
On Sun, Mar 20, 2016 at 10:44:57PM +0100, Patrick Tschackert wrote:
> After rebooting the system, one of the harddisks was missing from my md raid 6 (the drive was /dev/sdf), so i rebuilt it with a hotspare that was already present in the system.
> I physically removed the "missing" /dev/sdf drive after the restore and replaced it with a new drive.
Exact commands involved for those steps?
mdadm --examine output for your disks?
> $ cat /sys/block/md0/md/mismatch_cnt
> 311936608
Basically the whole array out of whack.
This is what you get when you use --create --assume-clean on disks
that are not actually clean... or if you somehow convince md to
integrate a disk that does not have valid data on, for example
because you copied partition table and md metadata - but not
everything else - using dd.
Something really bad happened here and the only person who
can explain it, is probably yourself.
Your best bet is that the data is valid on n-2 disks.
Use overlay https://raid.wiki.kernel.org/index.php/Recovering_a_failed_software_RAID#Making_the_harddisks_read-only_using_an_overlay_file
Assemble the overlay RAID with any 2 disks missing (try all combinations) and see if you get valid data.
Regards
Andreas Klauer
next prev parent reply other threads:[~2016-03-20 22:37 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <trinity-235b76ed-571d-4615-b6f7-b4d5ed6a116d-1458509365312@3capp-gmx-bs09>
2016-03-20 21:44 ` problems with dm-raid 6 Patrick Tschackert
2016-03-20 22:37 ` Andreas Klauer [this message]
2016-03-21 12:42 ` Phil Turmel
2016-03-21 13:27 ` Andreas Klauer
2016-03-21 21:26 ` Chris Murphy
2016-03-21 21:38 ` Andreas Klauer
2016-03-21 21:46 ` Chris Murphy
2016-03-21 22:42 ` Patrick Tschackert
2016-03-21 22:54 ` Adam Goryachev
2016-03-21 23:15 ` Andreas Klauer
2016-03-21 23:48 ` Adam Goryachev
2016-03-21 23:04 ` Andreas Klauer
2016-03-22 3:53 ` Chris Murphy
2016-03-22 4:22 ` Chris Murphy
2016-03-21 22:06 Patrick Tschackert
-- strict thread matches above, loose matches on Subject: below --
2016-03-21 22:19 Patrick Tschackert
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