Calamares doesn't create a proper BTRFS installation (no subvolumes)

[DeskworkTrickster]

Describe the bug

When using the Calamares GUI installer it doesn't seem to be possible to create a proper BTRFS installation with subvolumes.
Creating the partitions works fine. But there is no option to configure subvolumes and there are none created automatically.

Steps To Reproduce

1. Download a 22.05 Live ISO
2. Use "manual partitioning" in the GUI installer to setup a BTRFS filesystem
3. Install the system

Expected behavior

The system gets installed with BTRFS and subvolumes.

Additional context

Consider making BTRFS (instead of EXT4) the default installation option when going for "erase disk", since it seems to become a wildly popular option for linux distros in general.

[etrigan63]

Yes, please! BTRFS offers a lot of features that would improve many aspects of NixOS! Compression per subvolume, snapshots, and many others. Be sure to also allow multiple drives to be incorporated. I have three drives in my main system (all BTRFS - one for /home and another for data /mnt/data besides the main drive at /).

[AldebaraanMKII]

Seconding this. BTRFS offers much more advantages over ext4 in this day and age of super fast cpus.