Pulled directly from the AIX sysadmin manual:
http://www.redbooks.ibm.com/abstract...5129.html?Open


The problem can be resolved by restoring the backup of the superblock
over the primary superblock using one of the following commands:

dd count=1 bs=4k skip=31 seek=1 if=/dev/lv00 of=/dev/lv00

The following command works only for AIX 4.x.

fsck -p /dev/lv00

Once the restoration process is completed, check the integrity of the
file system by issuing the fsck command.

fsck /dev/lv00

In many cases, restoration of the backup of the superblock to the
primary superblock will recover the file system. If this does not
resolve the problem, recreate the file system and restore the data from
a backup.


--
Dana French