Ext3 users - Oct 2007 - Bad magic number in super-block

Hi,

After a power failure, I can't mount one of my partitions anymore. Here is
what I get from fsck:

--
fsck.ext3 /dev/sdb1
e2fsck 1.39 (29-May-2006)
Couldn't find ext2 superblock, trying backup blocks...
fsck.ext3: Bad magic number in super-block while trying to open /dev/sdb1

The superblock could not be read or does not describe a correct ext2
filesystem. If the device is valid and it really contains an ext2
filesystem (and not swap or ufs or something else), then the superblock
is corrupt, and you might try running e2fsck with an alternate superblock:
e2fsck -b 8193 <device>
--

I tried to give the suggested superblock as parameter but I get the same
error message. And with dumpe2fs and tune2fs as well.
Since I can't get the backup-superblock positions with dumpe2fs, I used a
block size of 1K and tried all the supposed-to-be backup superblocks but it
does not help.

Is there anything I can try to mount the partition again?

Cheers,
NiCd
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Hi Nickel Cadmium,

First, try running the command (as root): fdisk -l

That should confirm whether /dev/sdb1 is a valid filesystem partition and not a 
swap partition.  Look for an ID of 83 which identifies valid filesystem
partitions.  A partition with ID of 82 is usually swap and won't have a
superblock.

That said, if /dev/sdb1 is not a valid filesystem partition, then choose one
that with an ID of 83 and looks like it has the majority of space.  Then you
should be able to use: dumpe2fs -h /dev/sdb2, for example, and see if you get 
any other errors or can then successfully mount the partition.

Sometimes after a reboot, the fdisk -l command reports partitions not in
partition table order and will assign different partition names than the ones
you may normally see to the disk/partition of interest.

-- Tom