[linux-lvm] recovering data from inside a partitioned lv

[Bryn M. Reeves]

On Mon, 2009-06-22 at 13:23 -0400, Anthony Clark wrote:
> Hi,
> 
> The following stupid mistake was made :(  A pv, vg and lv were  
> created, and then the documentation was misread, and a partition was  
> created inside the lv.  Said partition mounted fine, and allowed fs  
> creation along with large amounts of data to be copied.  Partition was  
> accessible via /dev/vg1/lv1p1.
> 
> Server has been rebooted, and now only /dev/vg1/lv1 is shown.  parted  
> can open the lv and shows 1 partition inside, but doesn't understand  
> ext3 volumes, so can't copy the partition to another disk.  tune2fs  
> can't see /dev/vg1/lv1p1, or I'd use that to change the fs type to ext2.
> 
> Is there a way to undo the stupid mistake and get at the partition  
> inside the logical volume?  That is to say, mount the partition, copy  
> the data out and then create the filesystem correctly.  Is there a way  
> to force /dev/vg1/lv1p1 to show up again?

kpartx -a /dev/vg1/lv1

Will create maps for all the partitions defined inside the LV. See man
kpartx for the remaining options.

Cheers,
Bryn.