Sunday, May 24, 2009

How To Recover Veritas Volume Manager RAID0 Volume

How To Recover Veritas Volume Manager RAID0 Volume


Veritas Volume Manager(VxVM) RAID0 volume has either stripe or
concatenation layout. Suppose a subdisk has being removed from RAID0
volume e.g vxdiskadm #4, the data in the volume will be corrupted. An
attempt to recover the volume data by putting back the original subdisk
into RAID0 volume e.g vxdiskadm #5 will give error message " appears to be
owned by disk group ".

The following procedure show how to recover the Raid0 volume in this
situation with the following assumptions:
(1) no physical disk or Lun has being replaced. All the disks are in good
& original position
(2) no destructive command has being run which affect the integrity of
VxVM configuration e.g initialize the removed disk.

If you are unsure on above assumption, stop proceeding & seek help from Sun.


Steps to Follow

These are the following steps to take:


1) record down relevent disk vtoc table
privlen=tag 15 slice sector count
privoffset=tag 15 slice first sector
publen=tag 14 slice sector count
puboffset=tag14 slice first sector

2) uninitialize disk
# vxdiskunsetup -C

3) re-initialize disk back to original private & public region with input
from step(1)
# vxdisksetup -i privlen=<> privoffset=<> publen=<> puboffset=<>

4) prtvtoc to confirm the newly rebuilded vtoc table
# prtvtoc /dev/dsk/cXtXdXs2
# vxdisk list
** vxdisk output privlen may be smaller that vtoc due to roundup, but
publen MUST match on both outputs

5) put disk back to dg
# vxdg -g -k adddisk =

6) recover plex/volume
# vxmend -g -o force off
** plex under OFFLINE state & volume DISABLED/ACTIVE
# vxmend -g on
** plex under STALE state & volume DISABLED/ACTIVE
# vxmend -g fix active
** plex under DISABLED/ACTIVE & volume DISABLED/NEEDSYNC
# vxvol -g start
** plex & volume are under ENABLE/ACTIVE

7) fsck & mount the volume

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