Re: Advice recovering from interrupted grow on RAID5 array

[NeilBrown <neilb@suse.de>]

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On Wed, 16 Oct 2013 09:02:52 -0400 John Yates <jyates65@gmail.com> wrote:

> On Wed, Oct 16, 2013 at 1:26 AM, NeilBrown <neilb@suse.de> wrote:
> > On Mon, 14 Oct 2013 21:59:45 -0400 John Yates <jyates65@gmail.com> wrote:
> >
> >> Midway through a RAID5 grow operation from 5 to 6 USB connected
> >> drives, system logs show that the kernel lost communication with some
> >> of the drive ports which has left my array in a state that I have not
> >> been able to reassemble. After reseating the cable connections and
> >> rebooting, all of the drives appear to be functioning normally, so
> >> hopefully the data is still intact. I need advice on recovery steps
> >> for the array.
> >>
> >> It appears that each drive failed in quick succession with /dev/sdc1
> >> being the last standing and having the others marked as missing in its
> >> superblock. The superblocks of the other drives show all drives as
> >> available. (--examine output below)
> >>
> >> >mdadm --assemble /dev/md127 /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1 /dev/sdf1 /dev/sdg1
> >> mdadm: too-old timestamp on backup-metadata on device-5
> >> mdadm: If you think it is should be safe, try 'export MDADM_GROW_ALLOW_OLD=1'
> >> mdadm: /dev/md127 assembled from 1 drives - not enough to start the array.
> >
> > Did you try following the suggestion and run
> >
> >  export MDADM_GROW_ALLOW_OLD=1
> >
> > and the try the --asssemble again?
> >
> > NeilBrown
> 
> Yes I did, thanks. Not much change though. It accepts the timestamp,
> but then appears not to use it.
> 
> mdadm --assemble /dev/md127 /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1
> /dev/sdf1 /dev/sdg1 --verbose
> mdadm: looking for devices for /dev/md127
> mdadm: /dev/sdb1 is identified as a member of /dev/md127, slot 4.
> mdadm: /dev/sdc1 is identified as a member of /dev/md127, slot 3.
> mdadm: /dev/sdd1 is identified as a member of /dev/md127, slot 2.
> mdadm: /dev/sde1 is identified as a member of /dev/md127, slot 0.
> mdadm: /dev/sdf1 is identified as a member of /dev/md127, slot 1.
> mdadm: /dev/sdg1 is identified as a member of /dev/md127, slot 5.
> mdadm: :/dev/md127 has an active reshape - checking if critical
> section needs to be restored
> mdadm: accepting backup with timestamp 1381360844 for array with
> timestamp 1381729948
> mdadm: backup-metadata found on device-5 but is not needed
> mdadm: added /dev/sdf1 to /dev/md127 as 1
> mdadm: added /dev/sdd1 to /dev/md127 as 2
> mdadm: added /dev/sdc1 to /dev/md127 as 3
> mdadm: added /dev/sdb1 to /dev/md127 as 4 (possibly out of date)
> mdadm: added /dev/sdg1 to /dev/md127 as 5 (possibly out of date)
> mdadm: added /dev/sde1 to /dev/md127 as 0
> mdadm: /dev/md127 assembled from 4 drives - not enough to start the array.


What about with MDADM_GROW_ALLOW_OLD=1 *and* --force ??

If that doesn't work, please add --verbose as well, and report the output.

NeilBrown

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