e2fsck: Bad magic number in super-block

M. Lewis cajun at cajuninc.com
Wed Nov 1 01:15:30 UTC 2006


I posted this to the Fedora-list, but thought I might get some 
additional information here as well.

I have a HD that refuses to mount with a 'bad magic number in 
super-block'. I'm running FedoraCore 6 x86_64.

[root at moe ~]# fdisk -l /dev/hdc

Disk /dev/hdc: 250.0 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

    Device Boot      Start         End      Blocks   Id  System
/dev/hdc1   *           1          13      104391   83  Linux
/dev/hdc2              14        9729    78043770   8e  Linux LVM


[root at moe ~]# mount -t ext3 /dev/hdc2 /Big-Drive/
mount: wrong fs type, bad option, bad superblock on /dev/hdc2,
        missing codepage or other error
        In some cases useful info is found in syslog - try
        dmesg | tail  or so

[root at moe ~]# e2fsck -b 11239425 /dev/hdc2
e2fsck 1.39 (29-May-2006)
e2fsck: Invalid argument while trying to open /dev/hdc2

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>

[root at moe ~]# !624
mke2fs -n /dev/hdc2
mke2fs 1.39 (29-May-2006)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
9764864 inodes, 19510942 blocks
975547 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
596 block groups
32768 blocks per group, 32768 fragments per group
16384 inodes per group
Superblock backups stored on blocks:
         32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 
2654208,
         4096000, 7962624, 11239424


I've tried 'e2fsck -b (superblock) /dev/hdc2 on all the superblocks 
listed above to no avail.

I've read about 'mke2fs -S' as being a possible solution, however I see 
that it is recommended as a last resort. Therefore I have held off on 
trying that method.

I'm afraid I'm toasted, however I'm still hopeful that I might recover 
some (or all) of my data.

Have I overlooked something?

Thanks,
Mike

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