Re: Mounting a disk using backup superblock (solved now)
>on Tue, Sep 04, 2001 at 05:03:08PM +0200, Stephan Hachinger
> (Stephan.Hachinger@gmx.de) wrote:
> >> Hello!
> >>
> >> Below you see a copy of the last thread I'm referring to. My HDD and
> >> especially the superblock no.1 is heavily demaged - but I now have
> managed
> >> to e2fsck the partition using the backup superblock number 32768.
Debugfs
> >> /dev/hda2 can also show me the contents of the partition, but "mount -t
> >> ext2 -o sb=32768 /dev/hda2 /mnt" just won't mount it and says "bad
magic
> >> number" etc. Can anyone please tell me what I'm missing? Does mount
> >> calculate the superblock offset in another way or should I give up
or???
> I
> >> need this data desperately as I mentioned. If anyone can help me,
thanks
> >> thousand times in advance.
> >
> >Can't help you on disk forensics, but I *strongly* recommend you image
> >the disk to known good media before you tweak with it. Your debug tools
> >should work on the disk image equally as with the physical disk, with
> >the added bonus that it's not likely to go bad (or worse).
>
> Hmm, if I'd only have a HDD to save the data, I would be happy :) ; then I
> could probably do dd if=/dev/hda2 of=/dev/xyz and e2fsck -
> b 32768 /dev/xyz, e2fsck would restore the first superblock and my
problems
> were gone... but I have no second hard disk which is that big :(.
>
> Cheers and thanks anyway,
>
> Stephan
OK, just wanted to tell you the solution - while the block number which must
be given to mount is based on the blocksize which is installed on the hard
disk (4k in my case), the block number which must be given to mount is
calculated on a 1k-block-basis, so I had to multiply 32768*4.
Cheers,
Stephan
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