From: Mike Hardy <mhardy@h3c.com>
To: Sam Hopkins <sah@coraid.com>
Cc: linux-raid@vger.kernel.org, jrs@abhost.net, support@coraid.com
Subject: Re: data recovery on raid5
Date: Fri, 21 Apr 2006 16:38:47 -0700 [thread overview]
Message-ID: <44496D07.4070009@h3c.com> (raw)
In-Reply-To: <8867c2a014b34d9c11ce162c4f5860af@coraid.com>
Recreate the array from the constituent drives in the order you mention,
with 'missing' in place of the first drive that failed?
It won't resync because it has a missing drive.
If you created it correctly, the data will be there
If you didn't create it correctly, you can keep trying permutations of
4-disk arrays with one missing until you see your data, and you should
find it.
-Mike
Sam Hopkins wrote:
> Hello,
>
> I have a client with a failed raid5 that is in desperate need of the
> data that's on the raid. The attached file holds the mdadm -E
> superblocks that are hopefully the keys to the puzzle. Linux-raid
> folks, if you can give any help here it would be much appreciated.
>
> # mdadm -V
> mdadm - v1.7.0 - 11 August 2004
> # uname -a
> Linux hazel 2.6.13-gentoo-r5 #1 SMP Sat Jan 21 13:24:15 PST 2006 i686 Intel(R) Pentium(R) 4 CPU 2.40GHz GenuineIntel GNU/Linux
>
> Here's my take:
>
> Logfiles show that last night drive /dev/etherd/e0.4 failed and around
> noon today /dev/etherd/e0.0 failed. This jibes with the superblock
> dates and info.
>
> My assessment is that since the last known good configuration was
> 0 <missing>
> 1 /dev/etherd/e0.0
> 2 /dev/etherd/e0.2
> 3 /dev/etherd/e0.3
>
> then we should shoot for this. I couldn't figure out how to get there
> using mdadm -A since /dev/etherd/e0.0 isn't in sync with e0.2 or e0.3.
> If anyone can suggest a way to get this back using -A, please chime in.
>
> The alternative is to recreate the array with this configuration hoping
> the data blocks will all line up properly so the filesystem can be mounted
> and data retrieved. It looks like the following command is the right
> way to do this, but not being an expert I (and the client) would like
> someone else to verify the sanity of this approach.
>
> Will
>
> mdadm -C /dev/md0 -n 4 -l 5 missing /dev/etherd/e0.[023]
>
> do what we want?
>
> Linux-raid folks, please reply-to-all as we're probably all not on
> the list.
>
> Thanks for your help,
>
> Sam
>
>
> ------------------------------------------------------------------------
>
> /dev/etherd/e0.0:
> Magic : a92b4efc
> Version : 00.90.00
> UUID : 8fe1fe85:eeb90460:c525faab:cdaab792
> Creation Time : Mon Jan 3 03:16:48 2005
> Raid Level : raid5
> Device Size : 195360896 (186.31 GiB 200.05 GB)
> Raid Devices : 4
> Total Devices : 5
> Preferred Minor : 0
>
> Update Time : Fri Apr 21 12:45:07 2006
> State : clean
> Active Devices : 3
> Working Devices : 4
> Failed Devices : 1
> Spare Devices : 1
> Checksum : 4cc955da - correct
> Events : 0.3488315
>
> Layout : left-asymmetric
> Chunk Size : 32K
>
> Number Major Minor RaidDevice State
> this 1 152 0 1 active sync /dev/etherd/e0.0
>
> 0 0 0 0 0 removed
> 1 1 152 0 1 active sync /dev/etherd/e0.0
> 2 2 152 32 2 active sync /dev/etherd/e0.2
> 3 3 152 48 3 active sync /dev/etherd/e0.3
> 4 4 152 16 0 spare /dev/etherd/e0.1
> /dev/etherd/e0.2:
> Magic : a92b4efc
> Version : 00.90.00
> UUID : 8fe1fe85:eeb90460:c525faab:cdaab792
> Creation Time : Mon Jan 3 03:16:48 2005
> Raid Level : raid5
> Device Size : 195360896 (186.31 GiB 200.05 GB)
> Raid Devices : 4
> Total Devices : 5
> Preferred Minor : 0
>
> Update Time : Fri Apr 21 14:03:12 2006
> State : clean
> Active Devices : 2
> Working Devices : 3
> Failed Devices : 3
> Spare Devices : 1
> Checksum : 4cc991e9 - correct
> Events : 0.3493633
>
> Layout : left-asymmetric
> Chunk Size : 32K
>
> Number Major Minor RaidDevice State
> this 2 152 32 2 active sync /dev/etherd/e0.2
>
> 0 0 0 0 0 removed
> 1 1 0 0 1 faulty removed
> 2 2 152 32 2 active sync /dev/etherd/e0.2
> 3 3 152 48 3 active sync /dev/etherd/e0.3
> 4 4 152 16 4 spare /dev/etherd/e0.1
> /dev/etherd/e0.3:
> Magic : a92b4efc
> Version : 00.90.00
> UUID : 8fe1fe85:eeb90460:c525faab:cdaab792
> Creation Time : Mon Jan 3 03:16:48 2005
> Raid Level : raid5
> Device Size : 195360896 (186.31 GiB 200.05 GB)
> Raid Devices : 4
> Total Devices : 5
> Preferred Minor : 0
>
> Update Time : Fri Apr 21 14:03:12 2006
> State : clean
> Active Devices : 2
> Working Devices : 3
> Failed Devices : 3
> Spare Devices : 1
> Checksum : 4cc991fb - correct
> Events : 0.3493633
>
> Layout : left-asymmetric
> Chunk Size : 32K
>
> Number Major Minor RaidDevice State
> this 3 152 48 3 active sync /dev/etherd/e0.3
>
> 0 0 0 0 0 removed
> 1 1 0 0 1 faulty removed
> 2 2 152 32 2 active sync /dev/etherd/e0.2
> 3 3 152 48 3 active sync /dev/etherd/e0.3
> 4 4 152 16 4 spare /dev/etherd/e0.1
> /dev/etherd/e0.4:
> Magic : a92b4efc
> Version : 00.90.00
> UUID : 8fe1fe85:eeb90460:c525faab:cdaab792
> Creation Time : Mon Jan 3 03:16:48 2005
> Raid Level : raid5
> Device Size : 195360896 (186.31 GiB 200.05 GB)
> Raid Devices : 4
> Total Devices : 5
> Preferred Minor : 0
>
> Update Time : Thu Apr 20 21:07:50 2006
> State : clean
> Active Devices : 4
> Working Devices : 5
> Failed Devices : 0
> Spare Devices : 1
> Checksum : 4cc84d59 - correct
> Events : 0.3482550
>
> Layout : left-asymmetric
> Chunk Size : 32K
>
> Number Major Minor RaidDevice State
> this 0 152 64 0 active sync /dev/etherd/e0.4
>
> 0 0 152 64 0 active sync /dev/etherd/e0.4
> 1 1 152 0 1 active sync /dev/etherd/e0.0
> 2 2 152 32 2 active sync /dev/etherd/e0.2
> 3 3 152 48 3 active sync /dev/etherd/e0.3
> 4 4 152 16 4 spare /dev/etherd/e0.1
next prev parent reply other threads:[~2006-04-21 23:38 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-04-21 23:11 data recovery on raid5 Sam Hopkins
2006-04-21 23:31 ` Mike Tran
2006-04-21 23:38 ` Mike Hardy [this message]
2006-04-22 4:03 ` Molle Bestefich
2006-04-22 7:43 ` David Greaves
2006-04-22 8:51 ` David Greaves
-- strict thread matches above, loose matches on Subject: below --
2006-04-22 18:57 Jonathan
2006-04-22 19:48 ` Molle Bestefich
2006-04-22 20:07 ` Jonathan
2006-04-22 20:22 ` Molle Bestefich
2006-04-22 20:32 ` Jonathan
2006-04-22 20:38 ` Molle Bestefich
2006-04-22 20:55 ` Jonathan
2006-04-22 21:17 ` Molle Bestefich
2006-04-22 21:42 ` Carlos Carvalho
2006-04-22 22:58 ` Molle Bestefich
2006-04-22 22:30 ` David Greaves
2006-04-22 23:17 ` Christian Pedaschus
2006-04-22 20:51 ` Molle Bestefich
2006-04-22 20:28 ` Carlos Carvalho
2006-04-23 2:46 ` Neil Brown
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