df -T
vgdisplay
lvcreate -n lv_data-snap -s -L 1G /dev/vg0/lv_data
mkdir /mnt/snap
mount /dev/vg0/lv_data_snap /mnt/snap -o ro
blkid
mount -o nouuid /dev/vg0/lv_data_snap /mnt/snap -o ro
df -h
umount /mnt/data
umount /mnt/snap/
lvconvert --merge /dev/vg0/lv_data_snap