I didn’t follow a guide but it was a simple process in the installer GUI.
Just to ensure that you are indeed experiencing the same issue, I would recommend to observe the lvs output during your large VM shutdown, as explained here. When I saw that my system behaves exactly the same (= slow deletion of the -bak), I was more confident to try out BTRFS.
What I did in the installer GUI to get a BTRFS system:
- Select Manual Partitioning: “I will configure partitioning”
- Delete all automatically created/previous partitions
- Set "New mount points will use the following partitioning scheme: " to Btrfs
- Click on “Click here to create them automatically”
- Observe the new partition entries: The boot partition is still ext4 but the partition mounted at / is now Btrfs
Good luck!