Re: reshape failure

[Tobias McNulty <tobias@caktusgroup.com>]

On Wed, Feb 16, 2011 at 3:32 PM, NeilBrown <neilb@suse.de> wrote:
> On Wed, 16 Feb 2011 10:46:32 -0500 Tobias McNulty <tobias@caktusgroup.com>
>> nas:~# mdadm --assemble /dev/md0 --backup-file=md0.backup /dev/sdc
>> /dev/sdd /dev/sde /dev/sdf /dev/sdg /dev/sdh
>> mdadm: Failed to restore critical section for reshape, sorry.
>>
>> Is my data lost for good?  Is there anything else I can do?
>
> Try above command with --verbose.
> If a message about "too-old timestamp" appears, run
>
>  export MDADM_GROW_ALLOW_OLD=1
>
> and run the command again.
>
> In either case, post the output.

Wow - it looks like that might have done the trick:

nas:~# mdadm --verbose --assemble /dev/md0 --backup-file=md0.backup
/dev/sdc /dev/sdd /dev/sde /dev/sdf /dev/sdg /dev/sdh
mdadm: looking for devices for /dev/md0
mdadm: /dev/sdc is identified as a member of /dev/md0, slot 3.
mdadm: /dev/sdd is identified as a member of /dev/md0, slot 2.
mdadm: /dev/sde is identified as a member of /dev/md0, slot 1.
mdadm: /dev/sdf is identified as a member of /dev/md0, slot 0.
mdadm: /dev/sdg is identified as a member of /dev/md0, slot 5.
mdadm: /dev/sdh is identified as a member of /dev/md0, slot 4.
mdadm:/dev/md0 has an active reshape - checking if critical section
needs to be restored
mdadm: too-old timestamp on backup-metadata on md0.backup
mdadm: Failed to find backup of critical section
mdadm: Failed to restore critical section for reshape, sorry.
nas:~# export MDADM_GROW_ALLOW_OLD=1
nas:~# mdadm --verbose --assemble /dev/md0 --backup-file=md0.backup
/dev/sdc /dev/sdd /dev/sde /dev/sdf /dev/sdg /dev/sdh
mdadm: looking for devices for /dev/md0
mdadm: /dev/sdc is identified as a member of /dev/md0, slot 3.
mdadm: /dev/sdd is identified as a member of /dev/md0, slot 2.
mdadm: /dev/sde is identified as a member of /dev/md0, slot 1.
mdadm: /dev/sdf is identified as a member of /dev/md0, slot 0.
mdadm: /dev/sdg is identified as a member of /dev/md0, slot 5.
mdadm: /dev/sdh is identified as a member of /dev/md0, slot 4.
mdadm:/dev/md0 has an active reshape - checking if critical section
needs to be restored
mdadm: accepting backup with timestamp 1297624561 for array with
timestamp 1297692473
mdadm: restoring critical section
mdadm: added /dev/sde to /dev/md0 as 1
mdadm: added /dev/sdd to /dev/md0 as 2
mdadm: added /dev/sdc to /dev/md0 as 3
mdadm: added /dev/sdh to /dev/md0 as 4
mdadm: added /dev/sdg to /dev/md0 as 5
mdadm: added /dev/sdf to /dev/md0 as 0
mdadm: /dev/md0 has been started with 5 drives and 1 spare.

Now I see this in /etc/mdstat:

md0 : active raid6 sdf[0] sdg[5](S) sdh[4] sdc[3] sdd[2] sde[1]
      5860543488 blocks super 0.91 level 6, 64k chunk, algorithm 2 [5/5] [UUUUU]
      [=>...................]  reshape =  9.9% (193691648/1953514496)
finish=97156886.4min speed=0K/sec

Is the 0K/sec something I need to worry about?

Thanks!
Tobias
-- 
Tobias McNulty, Managing Partner
Caktus Consulting Group, LLC
http://www.caktusgroup.com
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