This is a small how-to to add an (encrypted) disk to an LVM Volume Group (VG). In this example, we’ll add /dev/sda to an existing volume group called howto-vg.

Encrypt the disk and open it:

cryptsetup luksFormat --type luks1 /dev/sda
cryptsetup open /dev/sda sda_crypt

Create the physical volume:

pvcreate /dev/mapper/sda_crypt

Make sure the volume group exists by running vgscan. Alternatively, you can use vgdisplay. Add the physical volume to the volume group:

vgextend howto-vg /dev/mapper/sda_crypt

And create the logical volume:

lvcreate -l 100%FREE howto-vg -n howto-volume

Create the filesystem on the logical volume:

mkfs.ext4 -m 1 /dev/howto-vg/howto-volume

Create the mount point so you can mount the volume:

mkdir -p /path/to/mount

You can now add the volume in /etc/fstab:

/dev/mapper/howto--vg-howto--volume  /path/to/mount	ext4	defaults	0	2

Now reload systemd by running systemctl daemon-reload.

Mount the disk by running mount /path/to/disk. The following step isn’t needed but cannot hurt either: reboot. After the reboot, you are sure the disk is mounted in the correct place. Yay.