Re: RAID5 disk failure during rebuild of spare, any chance of recovery when one of the failed devices is suspected to be intact?

[Nicolas Jungers <nicolas@jungers.net>]

I'd try to recreate the array with a copy of the disks

do a ddrescue of the 3 good disks and then try a mdadm -C with the exact 
parameters of the array creation with the same mdadm version (use 
missing for slot 2).  It saved my raid10 array.

N.


On 08/16/2010 12:33 AM, Tor Arne Vestbø wrote:
> On Sun, Aug 15, 2010 at 10:06 PM, Tor Arne Vestbø<torarnv@gmail.com>  wrote:
>> On Sun, Aug 15, 2010 at 8:52 PM, Tor Arne Vestbø<torarnv@gmail.com>  wrote:
>>> Hey,
>>>
>>> Hoping for some crisis help here :)
>>
>> Here's a few logs if it helps...
>
> After reading various tips on recovering I tried the following:
>
> # mdadm -Afv /dev/md0 /dev/sdb1 /dev/sdc1 /dev/sde1
> mdadm: looking for devices for /dev/md0
> mdadm: /dev/sdb1 is identified as a member of /dev/md0, slot 4.
> mdadm: /dev/sdc1 is identified as a member of /dev/md0, slot 1.
> mdadm: /dev/sde1 is identified as a member of /dev/md0, slot 3.
> mdadm: no uptodate device for slot 0 of /dev/md0
> mdadm: no uptodate device for slot 2 of /dev/md0
> mdadm: added /dev/sde1 to /dev/md0 as 3
> mdadm: added /dev/sdb1 to /dev/md0 as 4
> mdadm: added /dev/sdc1 to /dev/md0 as 1
> mdadm: /dev/md0 assembled from 2 drives and 1 spare - not enough to
> start the array.
>
> Thinking that since sdb1 was more or less intact it would be able to
> jump in and work together with sdc1 and sde1 to form a degraded array
> I could pull data off of.
>
> But it seems that when I added sdb1 to the array earlier after it
> initially was kicked for being "non-fresh", it got added as a spare,
> in slot 4.
>
> The message about no uptodoate device for slot 2 is correct, that's
> the sdd1 device that failed. But for slot 0 it should be sdb1.
>
> Is ther any way I can tell mdadm to assume sdb1 is up to date, and use
> that at slot 0?
>
> Thanks!
>
> Tor Arne
>
> PS: Pastebin.com seems to be down, so here's a repaste of mdadm -E:
> http://pastebin.org/518816
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