Re: [RFH] Partion table recovery

[Jan Engelhardt <jengelh@computergmbh.de>]

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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