The process for this is a bit confusing, but I think I got it (thanks @cmurf, for the help).
-
(Optional) Clean out any data you don’t need (empty trash etc.). This isn’t required, but will speed things up.
-
Edit /etc/fstab/ to look something like this:
UUID=123456789 / btrfs subvol=root,compress=zstd:1 0 0
UUID=123456789 /boot ext4 defaults 1 2
UUID=123456789 /boot/efi vfat umask=0077,shortname=winnt 0 2
UUID=123456789 /home btrfs subvol=home,compress=zstd:1 0 0
Take note especially of compress=zstd:1, the only change you should need to make. Systems not on UEFI should be about the same, just without /boot/efi.
-
Remount: sudo mount -o remount / /home/
-
Defrag/Compress.
sudo btrfs filesystem defrag -czstd -rv / /home/$USER
This may take a little while, but not too long, especially on an SSD. You can also do other things while it is going since any new writes should be compressed.
Afterwards you can see the difference it has made with sudo compsize -x / /home/$USER
If this isn’t included in the announcement, I think there should be something about it either in a magazine article or commblog (which I would be willing to write a prettier version for if need be) as it is a very cool feature that many may overlook.