There are a two different pages that address how to setup manual full disk encryption "LVM on LUKS". There are a few differences between the askubuntu answer and blog.botux.fr entry
The mount point names are different (cryptcherries
vs CryptDisk
) but this has no functional impact
The askubuntu answer explains how to zero out the newly created encrypted disk after the sudo cryptsetup luksOpen /dev/sda3 cryptcherries
which the blog.botux.fr entry does not.