This message from fsck(1M) indicates that a file system's super block is damaged beyond repair and must be replaced. At boot time (with the -p option) this message is prefaced by the file system's device name. After this message comes the actual damage recognized (see Action). Unfortunately, fsck(1M) does not print the number of the damaged super block.
The most common cause of this error is overlapping disk partitions. Do not immediately rerun fsck(1M) as suggested by the lines that display after the error message. First, make sure that you have a recent backup of the file system involved; if not, try to back up the file system now using ufsdump(1M). Then, run the format(1M) command, select the disk involved, and print out the partition information.
# format : N > partition > print |
# newfs -N /dev/dsk/device |
# fsck -o b=NNNN /dev/dsk/device |
Specific reasons for a damaged super block include: a wrong magic number, an out-of-range number of cylinder groups (NCG) or cylinders per group (CPG), the wrong number of cylinders, a preposterously large super block size, and trashed values in super block. These reasons are generally not meaningful, because a corrupt super block is usually extremely corrupt.
For more information on bad super blocks, see the sections on restoring bad super blocks in the System Administration Guide, Volume 1. If you are using AnswerBook online documentation, "super block" is a good search string.