Re: [RFH] Partion table recovery


On Jul 20 2007 07:35, Willy Tarreau wrote:
On Fri, Jul 20, 2007 at 08:13:03AM +0300, Al Boldi wrote:
As always, a good friend of mine managed to scratch my partion table by
cat'ing /dev/full into /dev/sda. I was able to push him out of the way, but
at least the first 100MB are gone. I can probably live without the first
partion, but there are many partitions after that, which I hope should
easily be recoverable.

Go use GPT, it's got a backup copy of the ptable at then end of the disk ;-)


I tried parted, but it's not working out for me. Does anybody know of a
simple partition recovery tool, that would just scan the disk for lost
partions?

The best one is simply "fdisk", because you can manually enter your
cylinders numbers. You have to find by hand the beginning of each partition,
and for this, you have to remember what filesystems you used and see how to
identify them (using a magic). Then with an hex editor, you scan the disk to
find such entries and note the possible sectors on a paper. Then comes fdisk.
You create the part, exit and try to mount it. If it fails, fdisk again and
try other values.

Pretty easy:
"XFSB" (offset +0),
"ReIsErFs2" (offset +0x10034),
"SWAPSPACE2" (offset +0xff6),
"FAT32" (offset +0x52h, maybe harder) / "mkdofs" (+0x3)
ext2/3 is TOUGH. (sequence 0x53ef at +0x438 - quite ambiguous!)


I've saved many disks that way, it may sound harder than it really is. It
should not take you more than half an hour to get the first part. Knowing
your approximate partitions size will help too.


Good luck!
Willy

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Jan
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