[linux-lvm] Backuping "special" snapshots

[Marc Patino Gómez <mpatino es clara net>]

Hi  list,

I am searching a way to backup a "special" logical volume. This special 
lv doesn't contains a filesystem, it contains a hole image disk of a 
running server (MBR,Partition Table, Partitions and filesystems), in 
fact it is a VBD (Virtual Block Device) of a HVM Xen Guest.

I want to be able to make the backup without shutting down the Virtual 
Machine, but the traditional way :

- make a snapshot
- mount snapshot
- backup the snapshots
- umount snapshot
- remove snapshot

is not suitable for this kind of logical volumes.

I search some information about it, but the only clue is:

fdisk -l -u /dev/vg00/lv00

after looking the partition table, mount a partition with mount with the 
corresponding offset parameter...

Exists a way to do this using a snapshot? Any other advice to backup 
this kind of logical volume?

Many thanks in advance,

Cheers,

Marc