Re: differnet UUIDs and no of spares :(

On Wed, January 14, 2009 10:50 pm, Bill Davidsen wrote:

Eamonn Hamilton wrote:

quoted

Hi Guys,


I'm looking at a server with a bunch of disks that had a raid 5 with
two spares, however, one of the spares failed, the system then started
rebuilding on the other and it crashed during the rebuild.

I'm now left in the following situation :



for a in a b c d e f g h i; do mdadm --examine --scan /dev/sd${a}; done
 ARRAY /dev/md0 level=raid5 num-devices=7
UUID=e1e75e8b:f9f387cd:5feed4c5:31c51eb2
ARRAY /dev/md0 level=raid5 num-devices=7
UUID=e1e75e8b:f9f387cd:5feed4c5:31c51eb2
ARRAY /dev/md0 level=raid5 num-devices=7
UUID=e1e75e8b:f9f387cd:5feed4c5:31c51eb2
ARRAY /dev/md0 level=raid5 num-devices=7
UUID=e1e75e8b:f9f387cd:5feed4c5:31c51eb2
ARRAY /dev/md0 level=raid5 num-devices=7
UUID=e1e75e8b:f9f387cd:5feed4c5:31c51eb2
ARRAY /dev/md0 level=raid5 num-devices=7
UUID=e1e75e8b:f9f387cd:8d12a2d2:3188faf0
spares=1 ARRAY /dev/md0 level=raid5 num-devices=7
UUID=e1e75e8b:f9f387cd:8d12a2d2:3188faf0
ARRAY /dev/md0 level=raid5 num-devices=7
UUID=e1e75e8b:f9f387cd:8d12a2d2:3188faf0
spares=1 ARRAY /dev/md0 level=raid5 num-devices=7
UUID=e1e75e8b:f9f387cd:8d12a2d2:3188faf0



The system complains because of the different uuids, and refuses to
recreate the array.

Is it basically stuffed, or is there something I can do to recover the
2TB filesystem that's on there ?

What can you tell us about how that happened? When (if ever) was it
running, how was it created, etc, etc.

You could probably try some things like trying to start it read-only
using --force, but don't do that yet, if you get it wrong you WILL be
likely to lose data.

--
Bill Davidsen [off-list ref]
"Woe unto the statesman who makes war without a reason that will still
be valid when the war is over..." Otto von Bismark

I don't suppose anybody else has any ideas? I've been holding off
attempting anything in the hope of somebody handing me a silver bullet,
but failing that ... ;)

Given that I still have the logs showing the order in which the drives
were assembled in these various phases, if I force a re-assembly in a
particular order, is there anything in the meta-data which would cause the
array to auto-magically continue where it left off?

Or should I simply take the afore-mentioned silver bullet, bite it and
recreate the whole lot as a RAID6, followed by the usual mad scrabbling
though old hard drives and tapes to try and get most of the content back?

Thanks in advance for any help,
Eamonn