Lvm snapshot

First, I added a new disk and did a pvcreate on it. Then I added the new disk to the same volume group that the root partition is in, namely "Ubuntu".

Command to create an lvm snapshot in order to do a backup of the root partition.

lvcreate -L250G -s -n root-snap /dev/Ubuntu/root

root@weasel:~# lvscan
File descriptor 5 left open
File descriptor 6 left open
File descriptor 7 left open
File descriptor 8 left open
  ACTIVE            '/dev/vg00/big' [232.88 GB] inherit
  ACTIVE   Original '/dev/Ubuntu/root' [226.77 GB] inherit
  ACTIVE            '/dev/Ubuntu/swap_1' [5.88 GB] inherit
  ACTIVE   Snapshot '/dev/Ubuntu/root-snap' [250.00 GB] inherit

Connect the USB drive where the backup will be stored.

Do the backup.

Verify the backup and disconnect the USB drive.

Destroy the snapshot.