More weird Flatpak confusion

[TwoFistedJustice]

First, I'm not sure what I'm asking here. I'm just sharing what I find and hoping for some insight on how I can do this better.

I'm experimenting with sharing Flatpaks between distros running on the same btrfs partition. It can be done.

The process in short as I have sussed it out:

1. Create a btrfs partition where flatpaks will live
2. Mount it from the distros you want to access the flatpaks
3. Install the flatpak in each distro with the "extra" configuration

I have Kubuntu and Kali sharing the same Firefox and DIYLC flatpaks.

It looks like when the flatpak installer sees that a flatpak already exists in the install folder, it makes a bunch of links. But I'm not sure. 'du' shows that the actual file usage doesn't change much when I do this. It's a few hundred kb more than if I install in just one distro. But the linked file space usage doubles, which is not surprising. (using du -l )


Here are some Disk Usage tables I made from du-ing Firefox and DIY Layout Creator (both from the original dev team)

On the basic directory structure:

Flatpak creates four directories which hold everything, and those run deep.

• app
• exports
• repo
• runtime

Record Size of Programs Directory Before and After Installs


After Firefox and DIY Layout Creator flatpaks installed in both distros:

FE = File Explorer
du = estimate file usage command
-l = count sizes many times if hard linked

All du measurements taken in Kubuntu after both installations were complete (I hadn't thought of measuring it yet)

All du measurements taken in Kubuntu


Note: the forum isn't showing the table column names.


This table is disk usage as show in file manager gui.
left: Kubuntu Dolphin ; Right : Kali File Manager

programs	1,295,025,103	3,015,458,075
app	252,367,100	252,411,743
exports	56,714	56,943
repo	1,262,806,120	1,291,525,513
runtime	1,039,342,822	1,471,463,876

The rest of the tables are all measured using the `du` command from Kubuntu Konsole

Right: du ; Left: du -l

programs	1,305,068	3,017,012
app	247,316	247,392
exports	96	96
repo	1,293,984	1,293,984
runtime	1,406,824	1,475,540

---

After DIY Layout Creator Installed in Kali ( but before installing it in Kubuntu ) (measured from Kubuntu)
Right: du ; Left: du -l

programs	1,305,068	3,017,012
app	247,316	247,392
exports	96	96 (120 in Kali)
repo	1,293,984	1,293,984
runtime	1,046,824	1,475,540

After DIY Layout Creator Installed in Kubuntu
Right: du ; Left: du -l

programs	1,667,564	3,741,828
app	608,652	609,736
exports	120	120
repo	1,656,432	1,656,432
runtime	1,046,824	1,475,540

Note: once both distros have DIYLC installed, du -l reads a few hundred Kb less in the very large folders.