Comment # 4 on bug 1180493 from Lukas Ocilka

The idea of keeping just one instance of Flatpak apps is interesting,
especially as they use quite some space. The (not only) only problem is, that
there is no Flatpak-specific partition on the system at all. At least not in
openSUSE. Flatpak apps are deployed into /var/lib/flatpak directory.

By default, openSUSE uses btrfs for most of the system parts and /var or
/var/lib might be subvolumes. Such setup does not seem to be compatible with
other distributions or even with other versions/instance of openSUSE when used
within the same computer.

What you are (?) asking for seems to be a new partition or LVM volume with some
kind of identifier $THIS_IS_FLATPAK_DIR - and this would be obviously working
only for system apps. In contrast to user-specific apps that are installed into
user's home.

This could be possibly addressed by extending the concept of discoverable
partitions https://systemd.io/DISCOVERABLE_PARTITIONS/ -- which is not (yet)
supported by [open]SUSE as it seems to bring more problems than benefits.

Keep in mind, that partition created just for Flatpak would occupy space that
could be used for something else. The problem seems to be smaller when using
LVM and space can be easily extended (more or less). Anyway, it's hard to
predict how big the partition should be.

Slawek, maybe I understood it in a different way, so could you PLS elaborate a
bit more about your ideas or expectations?