Superblock recovery from backup block 32

Ernie Elu ernie at
Mon May 26 07:30:53 PDT 2003

I have an IDE drive running FreeBSD 4.8-RELEASE that had a superblock
corruption on the / partition as a result of a faulty motherboard.

When I do an fsck_ffs -o -b 32 /dev/ad2s2a  it passes all the scans.

However after that fsck_ffs /dev/ad2s2a still fails:

root # fsck_ffs /dev/ad2s2a               
** /dev/ad2s2a
Cannot find file system superblock
/dev/ad2s2a: INCOMPLETE LABEL: type 4.2BSD fsize 0, frag 0, cpg 0, size 13211287

I did a fair bit of reading the archives and I thought that fsck is meant to
replace the faulty superblock automatically when you specify an alternative
with the -b flag, but that is not happening.

Can anyone tell me how to replace the superblock with the copy at block 32
which still seems to be o.k?

More information about the freebsd-fs mailing list