Disk Recovery - Part II

[rlk at alum.mit.edu (Robert L Krawitz)]

   From: "Don Levey" <lug at the-leveys.us>
   Date: Fri, 16 Dec 2005 13:11:03 -0500

   Rich wrote:

   > Bottom line:  the rsync command will generate a lot of head seeks.
   > The dd command won't.  Depending on the nature of the drive's failure
   > (are more bad blocks appearing as you use the drive?) you might want
   > to consider this fact as you attempt recovery.

   I can't mount the partition in question at all, and I'm not seeing anything
   to suggest bad blocks in other partitions.

I think Rich is right -- dd the partition off to a file (on another
disk!).  You can then fsck the file (I don't think fsck really cares
what it's doing, just so long as whatever file it's asked to check has
the right semantics) and mount this image via a loopback mount when
you really want to copy it.

I've done this kind of thing before when I had a failing disk in my
laptop; it's not actually all that hard.  The only problem I had was
that a couple of unreadable sectors wrecked the dd.  I think that
there's at least some version of dd around that can work around
unreadable sectors.  Incidentally, I got very lucky with my laptop
drive -- it was a thermal issue, and as long as I kept the drive cool
I was able to get data off it.  The only two files I lost were the
boot log and the X server session log, probably about the least
important files on the disk.