From: travis+ml-linux-raid@subspacefield.org
To: linux-raid@vger.kernel.org
Subject: SOLVED - Re: md raid0 with overwritten superblock on 1/4 disks
Date: Sun, 2 Feb 2014 17:24:05 -0800 [thread overview]
Message-ID: <20140203012405.GB7193@subspacefield.org> (raw)
In-Reply-To: <20140203004137.GA7193@subspacefield.org>
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Funny how the answer is obvious once you ask.
I noticed the "Data Offset" was 2048 sectors.
On the newly-created md, it was 16 sectors, I think because it was a
device mapper overlay and not a real block device.
I found this page:
http://www.thomas-krenn.com/en/wiki/Linux_Software_RAID
Got the mdadm development version that allows setting data offset.
724 parallel truncate -s4000G overlay-{/} ::: $DEVICES
725 parallel 'size=$(blockdev --getsize {}); loop=$(losetup -f --show -- overlay-{/}); echo 0 $size snapshot {} $loop P 8 | dmsetup create {/}' ::: $DEVICES
726 cat /proc/mdstat
727 mdadm -S /dev/md127
728 ~/src/mdadm-40c9a66/mdadm --create /dev/md127 --data-offset=1024 -v -l 0 -n 4 $OVERLAYS
That fixed it up (data offset is in k, not sectors).
Cheers.
--
http://www.subspacefield.org/~travis/
Remediating... LIKE A BOSS
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prev parent reply other threads:[~2014-02-03 1:24 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-03 0:41 md raid0 with overwritten superblock on 1/4 disks travis+ml-linux-raid
2014-02-03 1:24 ` travis+ml-linux-raid [this message]
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