undo LVM

[Michel Racic]

2010/5/18 Dave Howorth <dhoworth at mrc-lmb.cam.ac.uk>:
> Luis Paulo wrote:
>> You made a good point, I agree.
>>
>> I was thinking that luks was a file encryption software, now I saw it
>> encrypts a partition (As I said, I know nothing about luks or
>> encryption)
>
> I don't know anything either but Michel said it was the whole disk.
>
>>> As its full disk encryption,
>>> /dev/sdb is the disk with the encrypted volume on
>
>> As far as I understood, from what was said, there is no reason to
>> think lvm has messed any of the luks information
>
> Well, the LVM is /dev/sdb1 so if what Michel wrote earlier is accurate,
> the entire LVM is inside the encrypted volume. So the LVM metadata has
> definitely overwritten some data. Since the encrypted volume won't
> mount, it seems likely that it was actually metadata. Even if it wasn't,
> I doubt whether overwriting a block in the middle of an encrypted volume
> loses just one block because encryption normally scatters information
> around. But maybe there's some error-correction or backups for metadata
> or something. Basically Michel needs to be looking for recovery tools
> for the encrypted volume. All this LVM stuff is a red herring.
>
> Cheers, Dave
>
> PS Of course, as long as he's working on a cloned disk, there's no
> danger whatever he does. He's just wasting time.
>
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I've done the dd (needed some hours to dd 1TB to another disk) and I
play around with testdisk now to see if it can do something...
>From my hexediting I fear that LVM wrote a lot of headers into the
disc and from the LUKS specification (not the implementation) it says
that the header should start at Block 0 and doesn't write any backups
to spread over the disc that can be taken like if restoring an ext3
FS...

@Luis: Sorry, I will write at the bottom of this thread when I write
from my PC but on the mobile I can't (it's just showing me the
textentry box and does the quoting by itself).
Is this special for mailing-list posts to preserve the structure of the posting?

@Dave: Yes of course the worst thing that can happen is that I just
waste some time but in return I get a good insight into File-systems
and how they work (I wished I would get it without going the hard way)
especially LVM and Luks container and I even learned something about
ext3 and how to recover superblocks from the backups inside the
partition.

I will keep you in the loop if I find something or get a step further
but I didn't convert to Linux a couple of years back (I think it was
SuSe in version 4) if I give up that fast ;-)

Regards Michel