[SATLUG] Disk recovery

[tom weeks]

On Wednesday 20 June 2007 15:39, Bruce Dubbs wrote:
> I have a friend with a corrupted disk.  Evidently this is part of a
> linksys backup system.  He removed the disk and put it into a PC.  After
> working with him I found out it was:
>
> Disk /dev/hdb:  81.9GB, 81964302336 Bytes
> 16 Heads, 63 Sectors/Track, 158816 Cylinders
> Units = Cylinders of 1008 * 512 = 516096 bytes
>
> Device boot        Start        End        Blocks        ID      System
> /dev/hdb1              2     158563      79915248        83      Linux
> /dev/hdb2         158564     158816        127512        82      Linux
> swap / Solaris
>
> We tried running e2fsck but it couldn't find a valid superblock.  I had
> him dump the block with the first superblock (2nd 1K block) and it was
> all zeros.

I'm assuming here that it IS either ext2 or 3.

If so..
Scan it for alternate super blocks:
# dumpe2fs /dev/sda2|grep super
dumpe2fs 1.39 (29-May-2006)
Filesystem features:      has_journal ext_attr resize_inode dir_index filetype 
needs_recovery sparse_super
  Primary superblock at 1, Group descriptors at 2-2
  Backup superblock at 8193, Group descriptors at 8194-8194
  Backup superblock at 24577, Group descriptors at 24578-24578
  Backup superblock at 40961, Group descriptors at 40962-40962
  Backup superblock at 57345, Group descriptors at 57346-57346
  Backup superblock at 73729, Group descriptors at 73730-73730


Then you can try fscking with one of those with:
# fsck  -b 73729


If it looks like it's going to work.. then use with the -y switch.

Tweeks