Why with this new app called AIDA64 my
Jolla C says
Android version: 5.1.1
Android API level: 22

Jolla phone says
Android version: 4.1.2
Android API level: 16

Jolla Tablet says
Android version: 4.4.4
Android API level: 19

I can post screenshots if needed

The only real problem (or: the cause of all problems) with btrfs on the Jolla is that it's really, really old. It works just fine on my computer, and it's even the default filesystem for enterprise server software.

100% agreed - it's an unfortunate consequence of manufacturers not providing the code of their drivers - we're stuck with an old kernel version thanks to Qualcomm and btrfs is the main victim.

Funny thing is, I never had any problem with btrfs on my Jolla, but I had to remove it from my desktop, as openSUSE's Snapper (on by default with btrfs) is absolutely insane, especially on SSDs. Few zypper'ups and you're stuck with an unbootable system due to full disk. But that's another story...

Oh yeah, no doubt about that. First thing I did after installing Leap was to disable everything related to snapper.

thanks for the info. can you install the App DJI Go on the Jolla C? On Jolla Phone 1 is it not possible to install

It's a no-go from Aptoide store.

There's absolutely nothing wrong with btrfs and I am actually sad Jolla decided to drop it.
In reality btrfs is fast, scalable, effcient and reliable, providing a good set of modern well-thought-of features.

Any and all FS'es run into trouble when users pump their partitions too full, there just needs to be enough leeway in the system.
My n9 had 64GB of storage which was enough at that time, what, almost 5 years ago. All the btrfs problems on Jolla stem from the laughable/cryable 16GB of storage....
In 5 years device minimum allowed storage size should have grown like Moore's law, making something like 256GB the norm now...

@juiceme there's plenty wrong with the J1's btrfs setup / version though.

As you allude to, a filesystem should not cave in on itself when you near capacity and/or put a load of small files on it, and then refuse to be able to clear that up because deleting files requires more journal space, and there's no space left. But at the same time perform file operations, just slowly, so that's it's not immediately clear what the problem with the system is.

I have had to manually delete caches and other things (looping through some xargs madness zeroing-then-deleting on loop until it worked) down to about 5gb allegedly-free on several occasions just in order to successfully run the balancer in order to get out of the "stuck" mode.

Obviously it was less effort to write a balancer daemon to run around tidying up than it was to backport or reconfigure btrfs to the J1 kernel. I imagine the whole debacle has soured them, especially as it only became obvious after people had had devices for over 6 months. Testing that kind of long-running gradually-worsening bug is a total nightmare so I imagine "ah screw it, let's use ext" was an appealing way out.

Yes, it was way less effort (says the author of that balancer daemon).

What Qt Version is installed? Still 5.2 ?