reconstructing an ext3 filesystem?

yello · 12-11-2007, 04:16 PM

OK, so I know this sounds like a nearly impossible task...

I have three ext3 filesystems that suddenly would not mount. The event that appears to have caused this was a failure in the RAID5 array that the filesystems resided on. Well, the RAID5 array has been repaired and the physical volume, volume group, and logical volumes once again exist.

But, when I try to fsck the filesystems, I get:

Code:

[root@hawaii ~]# fsck.ext3 /dev/raid5a/homes
e2fsck 1.40.2 (12-Jul-2007)
Couldn't find ext2 superblock, trying backup blocks...
fsck.ext3: Bad magic number in super-block while trying to open /dev/raid5a/homes

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@hawaii ~]#

I have tried 'e2fsck' with some alternate superblocks, but I get the same message.

I have also tried using some recovery programs (e.g. foremost) but they don't recover things very nicely (e.g. most of the files only get partially recovered, only the smallest survive). Suggestions welcome here...

I have dd'd the volume to a file and viewed the data and I can see the filenames and the directory names that I had on the volume. I have also tried 'dd' to copy the volume to a clean volume, but, as expected, I get the same message as above.

What's going on here?

What would cause all three of these volumes to 'disappear'?

And, what do I do about it?

I have backups but not of the data added most recently and I'd really like to get it back.

Can anybody shed some light here?

Thanks,
--dave;

pljvaldez · 12-11-2007, 04:51 PM

You can try using testdisk to repair the filesystem and/or photorec to recover files. I like to only do one filetype at a time...

yello · 12-13-2007, 02:01 PM

Tried your suggestions...Thanks.

testdisk would not recognize my filesystem (as it is not on a physical disk, but several via RAID5 and LVM). I tried 'dd' to copy the logical volume to a single physical disk. Then, testdisk would report that I had a "bad /" and I couldn't list any of the files. Could this have to do with the fact that I tried to copy it to another device?

I also tried 'photorec' on this new volume and it found 11,000 jpg files, but, it seems, that each one is either invalid or incomplete. Very frustrating.

Could it be something in the way that I'm copying the volume?

# dd if=/dev/raid5a/photos of=/dev/sdd1 bs=1024

Any help is appreciated,

--dave;