After a power cycle, the machine displays either of the following error messages:
corrupt label - label checksum failed
corrupt label - wrong magic number
0 unassigned wm 0 0 (0/0/0) 0 1 unassigned wm 0 0 (0/0/0) 0 2 backup wm 0 - 5460 4.2G (5460/0/0) 4154160 3 unassigned wm 0 0 (0/0/0) 0 4 unassigned wm 0 0 (0/0/0) 0 5 unassigned wm 0 0 (0/0/0) 0 6 unassigned wm 0 - 2730 2.1G (0/0/0) 0 7 unassigned wm 2730-5460 2.1G (0/0/0) 0 |
The disks were using raw partitions beginning at block 0 (cylinder 0). The disk label (VTOC) is kept on the block 0 of cylinder 0. The label eventually gets overwritten by database programs using raw partitions, if the raw partition begins at cylinder 0. (UNIX® file systems avoid this area of the partition.)
As a workaround, do the following:
Go into format(1M) and get the backup label using the backup command.
Relabel the disk using this backup label. You should then be able to access the disk.
Backup the data on this disk.
Go back to the disk and relabel it, starting the raw partition at cylinder 1. (This loses one cylinder, but prevents corrupting the VTOC.)
Label again.
Restore the data from your backup.