A volume group on a spare disk, an ext4 logical volume mounted at boot, growing it onto a second disk while it's mounted, and getting a deleted file back by merging a snapshot.

Before you start

The lab adds two empty spare disks: /dev/loop40 (1 GiB, the first) and /dev/loop41 (2 GiB, the second). They come back at every boot. The LVM tools are installed.

Tasks

Make a volume group vg1 from the first spare disk and an 800 MiB logical volume home2 with ext4, mounted at /mnt/home2 at every boot.
Grow home2 by 1.5 GiB, adding the second disk to the group first if needed, without unmounting it.
Create a file /mnt/home2/notes.txt, snapshot home2, delete notes.txt, and get it back by merging the snapshot.

Hints

pvcreate, vgcreate, lvcreate -L 800M -n, mkfs.ext4; an /etc/fstab line for /dev/mapper/vg1-home2 (or its UUID), then systemctl daemon-reload and mount -a.
vgs vg1 shows the free space; vgextend, then lvextend -r -L +1.5G grows the filesystem too. df -h /mnt/home2 should show about 2.3G.
lvcreate -s -L 200M -n NAME vg1/home2; unmount, lvconvert --merge vg1/NAME, mount again. lvs vg1 no longer lists the snapshot.