8.6.4. Removing a Backing Device

Before a backing device can be removed, client LPARs should stop using the backing device. And the corresponding physical volume in the client LPAR should be removed first. This is not shown here.

If a backing device is no longer required, it can be deleted using the “vios rmbdsp” command (remove backing device from storage pool):

$ vios rmbdsp ms05-vio1 testpool bd001

The backing device is irrevocably deleted and cannot be restored, unless the data has been backed up. You should therefore be absolutely sure that the backing device is no longer in use by the client LPAR and that the data on the backing device is no longer needed.

Deleting the backing device on the virtual I/O server does not result in an error message if the client LPAR is still using the backing device!

If the associated physical volume in the client LPAR is still in use, every I/O on the physical volume will fail:

lpar1 # lsvg -p vg00
0516-062 : Unable to read or write logical volume manager
        record. PV may be permanently corrupted. Run diagnostics
lpar1 #

If you only want to remove the mapping first, but not delete the backing device itself, the “vios unmap” command should be used:

$ vios unmap ms05-vio1 bd001

The backing device and the data are then retained and only access by the client LPAR is no longer possible. In the worst case, the backing device can be reassigned (re-mapped) and the data can then be accessed again.