From: Phil Turmel <philip@turmel.org>
To: lists@yazzy.org
Cc: linux-raid@vger.kernel.org
Subject: Re: Recovery of failed RAID 6 and LVM
Date: Sun, 25 Sep 2011 09:15:40 -0400 [thread overview]
Message-ID: <4E7F297C.9070403@turmel.org> (raw)
In-Reply-To: <4E7EDE58.3000804@yazzy.org>
On 09/25/2011 03:55 AM, Marcin M. Jessa wrote:
> Hi guys.
>
>
> I have a RAID 6 setup with 5 2TB drives on Debian Wheezy [1] & [2].
> Yesterday 3 of the drives failed working leaving the RAID setup broken.
> Following [5] I managed to start the array and make it resync.
> The problem I'm facing now is I cannot access any of the LVM partitions [3] I have on top of my md0. Fdisk says the disk doesn't contain a valid partition table [4].
> I tried to run fsck on the lvm devices without luck.
> Has any of you a suggestion, a method I could use to access my data please?
[trim /]
> [5]: http://en.wikipedia.org/wiki/Mdadm#Recovering_from_a_loss_of_raid_superblock
These instructions are horrible! If you make the slightest mistake, your data is completely hosed.
If first asks for your "mdadm -E" reports from the drives, but it has you filter them through a grep that throws away important information. (Did you keep that report?)
Next, it has you wipe the superblocks on the array members, destroying all possibility of future forensics.
Then, it has you re-create the array, but omits "--assume-clean", so the array rebuilds. With the slightest mistake in superblock type, chunk size, layout, alignment, data offset, or device order, the rebuild will trash your data. Default values for some of those have changed in mdadm from version to version, so a naive "--create" command has a good chance of getting something wrong.
There is no mention of attempting "--assemble --force" with your original superblocks, which is the correct first step in this situation. And it nearly always works.
I'm sorry, Marcin, but you shouldn't expect to get your data back. Per your "mdadm -D" report, the rebuild was already 63% done, so the destruction of your data is certainly complete now.
Regards,
Phil
next prev parent reply other threads:[~2011-09-25 13:15 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-25 7:55 Recovery of failed RAID 6 and LVM Marcin M. Jessa
2011-09-25 8:39 ` Stan Hoeppner
2011-09-25 10:07 ` Marcin M. Jessa
2011-09-25 13:15 ` Phil Turmel [this message]
2011-09-25 14:16 ` Marcin M. Jessa
2011-09-25 16:43 ` Phil Turmel
2011-09-25 14:41 ` Marcin M. Jessa
2011-09-25 16:19 ` Phil Turmel
2011-09-25 21:40 ` NeilBrown
2011-09-25 21:58 ` Marcin M. Jessa
2011-09-25 22:18 ` NeilBrown
2011-09-25 22:21 ` Marcin M. Jessa
[not found] ` <4E804062.3020700@yazzy.org>
2011-09-26 9:31 ` NeilBrown
2011-09-26 10:53 ` Marcin M. Jessa
2011-09-26 11:10 ` NeilBrown
2011-09-27 19:12 ` Marcin M. Jessa
2011-09-27 23:13 ` NeilBrown
2011-09-28 2:50 ` Stan Hoeppner
2011-09-28 7:10 ` Marcin M. Jessa
2011-09-28 7:51 ` David Brown
2011-09-28 16:12 ` Stan Hoeppner
2011-09-28 16:30 ` Marcin M. Jessa
2011-09-28 18:56 ` Thomas Fjellstrom
2011-09-28 19:26 ` Marcin M. Jessa
2011-09-28 19:42 ` Thomas Fjellstrom
2011-09-28 23:49 ` NeilBrown
2011-09-29 9:03 ` David Brown
2011-09-29 15:21 ` Stan Hoeppner
2011-09-29 17:14 ` David Brown
2011-09-29 18:28 ` Dan Williams
2011-09-29 23:07 ` NeilBrown
2011-09-30 0:18 ` Williams, Dan J
2011-10-05 2:15 ` NeilBrown
2011-09-28 10:38 ` Michal Soltys
2011-09-28 13:20 ` Brad Campbell
2011-09-28 19:02 ` Thomas Fjellstrom
2011-09-28 16:31 ` Stan Hoeppner
2011-09-28 16:37 ` Marcin M. Jessa
2011-09-28 19:03 ` Thomas Fjellstrom
2011-09-28 19:29 ` Marcin M. Jessa
2011-09-28 19:43 ` Thomas Fjellstrom
2011-09-30 20:01 ` Marcin M. Jessa
2011-09-30 21:47 ` Thomas Fjellstrom
2011-09-30 22:30 ` Marcin M. Jessa
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4E7F297C.9070403@turmel.org \
--to=philip@turmel.org \
--cc=linux-raid@vger.kernel.org \
--cc=lists@yazzy.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.