Guru wanted: lvm volume is corrupt.

echo_max · 10-30-2009, 02:22 PM

Hey all. First off, this is for personal data so please don't waste too much of your efforts. But any help is greatly appreciated!

A little background first:
I've got, well...had, a volume group created with LVM2. Created with two 500G external HDDs and i believe the volume group was a raid 1. I have these drives housed inside an external case with SATA connections going into the system. One day while I was away the power to the external case got disconnected and created some bad problems. The system itself wasn't shutdown, it was running normally, just the power to the HDDs

My current problem I believe lies with just one of the hard drives. When lvm tries to bring up this volume, it complains that it cannot find one of the devices' UUID. I can't seem to find either of the hdd UUIDs so i'm not sure if the power corrupted both drives. I can bring up one of the drives in fdisk and the partion table looks fine, however, with the second hdd the partition table is corrupt.

Here is output from one lvm command. All other lvm commands print out the same error for this lvm:

Code:

lvm> vgscan
  Reading all physical volumes.  This may take a while...
  Couldn't find device with uuid 'MCgCMw-jaAV-tQd6-FoAo-UbM4-lHNG-tX2USr'.
  Couldn't find all physical volumes for volume group lvm1.
  Couldn't find device with uuid 'MCgCMw-jaAV-tQd6-FoAo-UbM4-lHNG-tX2USr'.
  Couldn't find all physical volumes for volume group lvm1.
  Volume group "lvm1" not found

So, any ideas or solutions? Is this scenario already at a dead end? I have little no nothing experience with data recovery so I'm not sure how feasible it is to get this data back. Seems to me like it is but thats a very naive statement.

Thanks for you help in advance.

unSpawn · 10-31-2009, 03:37 AM

Quote:

Originally Posted by echo_max

this is for personal data so please don't waste too much of your efforts.

LQ members may use GNU/Linux for personal and professional reasons so the distinction does not matter when troubleshooting.

Quote:

Originally Posted by echo_max

My current problem I believe lies with just one of the hard drives. When lvm tries to bring up this volume, it complains that it cannot find one of the devices' UUID. I can't seem to find either of the hdd UUIDs so i'm not sure if the power corrupted both drives. I can bring up one of the drives in fdisk and the partion table looks fine, however, with the second hdd the partition table is corrupt.

If it's a RAID1 shouldn't you use 'mdam' to --examine and --scan the array members first, break out the "bad" one and -a it back in to facilitate rebuilding the mirror before mucking with LVM tools? Wrt LVM, do you have an external backup of LVM headers (/etc/LVM/backup contents)?