Re: [linux-lvm] accidently formatted a physical volume...

[Andreas Dilger <adilger@clusterfs.com>]

On Aug 20, 2002  13:20 -0500, Kirby C. Bohling wrote:
> In the end, LVM is an abstraction for a block device.  So I'd create 
> a file and connect a loopback that was the same size as the LV.  So pull a 
> physical extent, figure out if it is associated with the lv you're 
> recovering.  Take the lv extent offset it is, and seek the extent size * 
> logical extent number and write it to the loopback device.  Throwing 
> away the LVM metadata.  Now, you can take this big pile of bits to an 
> ext2/3 guru, and ask them how to glean as much data as possible out of 
> it.  If the LV was completely on one disk, it should just fsck and 
> mount.  Assuming you didn't specify the sizes, and do a lot of resizing 
> of the LV's that should be the case.  Possibly asking the ext2/3 guru 
> what the holes should be filled in with, and put that there. I'd guess 
> zero's.  This trick should work on both sets of disks, but it'll be 
> easier to pull off with known good meta-data.

Run something like "gpart" or build the findsuper program in
e2fsprogs/misc, which should give you a pretty good idea of where things
are put on the disk.

Cheers, Andreas
--
Andreas Dilger
http://www-mddsp.enel.ucalgary.ca/People/adilger/
http://sourceforge.net/projects/ext2resize/