Ext3 users - Mar 2007 - whoops, corrupted my filesystem

Hi all-

I corrupted my filesystem by not doing a RTFM first...  I got an automated 
email that the process monitoring the SMART data from my hard drive detected 
a bad sector.  Not thinking (or RTFMing), I did a fsck on my partition- 
which is the main partition.  Now it appears that I've ruined the 
superblock.

I am running Fedora Core 6.  I am booting off the Fedora Core 6 Rescue CD in 
order to try to fix things (my system isn't bootable.)

Doing a e2fsck /dev/hda2 tells me that the superblock is corrupt.   When I 
do a mke2fs -n /dev/hda2, it tells me that other backups are stored on 
32768, 98304, 16840, 229376, 294912, 819200, 884736, 1605632, 265???? (cut 
off), 4096000, 7962624, 11239424, 20480000, 23887872.

When I try doing a e2fsck -b xxx /dev/hda2, on any of the superblocks <= 
4096000 I get the message that it's corrupted.  When I do >= 7962625, I
get
"Invalid argument while trying to open /dev/hda2."

By the way, there's some sort of weird Logical Volume thing going on with 
this partition.  On an old (out of date unfortunately) backup, the mtab file 
has it listed as /dev/mapper/VolGroup00-LogVol00.  Perhaps this partition 
can't be addressed as /dev/hda2 and it should be addressed differently??

Should I try a mke2fs -S on this drive or is there something else I should 
try first?  Everything I've read says to back up before mke2fs -S ing.  I 
have an external ext3 drive with enough space to hold this mangled partition 
on it, although it currently has a single ext3 partition.  Is there a way to 
copy the contents of the mangaled partition to the external ext3 partition 
w/o deleting what's already on it or resizing it and creating a 2nd 
partition?

If it is suggested that I try a mke2fs -S, how does that work?  mke2fs -n 
tells me that:

Block size=4096 (log=2)
Fragment size=4096 (log=2)
30523392 inodes, 61022902 blocks
3051145 blocks
First data block=0
Maximum filesystem blocsk=0
1863 block groups
32768 blocks per group, 32768 fragments per group
16384 inodes per group

Thanks much for any help!  I'd love to recover this instead of having to 
rebuild my linux PC!

Andrew


ps- This is a 250 GB Parallel ATA drive.

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On Mar 01, 2007  16:21 -0500, Andy Lindeman wrote:
> Doing a e2fsck /dev/hda2 tells me that the superblock is corrupt.   When I 
> do a mke2fs -n /dev/hda2, it tells me that other backups are stored on 
> 32768, 98304, 16840, 229376, 294912, 819200, 884736, 1605632, 265???? (cut 
> off), 4096000, 7962624, 11239424, 20480000, 23887872.
> 
> When I try doing a e2fsck -b xxx /dev/hda2, on any of the superblocks <=
> 4096000 I get the message that it's corrupted.  When I do >=
7962625, I get
> "Invalid argument while trying to open /dev/hda2."
> 
> By the way, there's some sort of weird Logical Volume thing going on
with
> this partition.  On an old (out of date unfortunately) backup, the mtab 
> file has it listed as /dev/mapper/VolGroup00-LogVol00.  Perhaps this 
> partition can't be addressed as /dev/hda2 and it should be addressed 
> differently??
Correct.  You should be running e2fsck /dev/mapper/VolGroup00-LogVol00
instead of /dev/hda2.  That's likely why your filesystem is
"corrupted"...

Cheers, Andreas
--
Andreas Dilger
Principal Software Engineer
Cluster File Systems, Inc.