I am on KDE. I expirienced for the first time I use Manjaro a very strange issue. I had 15GB free space available. Download was about 2GB and estimation after instalation about 6,5GB. But when instalation was going on system run out of space. I reverted changes from backup but this happend again and again. Maybe some packages have problem with being unpacked and multiply themeselves…
Last time it happend the package processed was oxygen icons.
Maybe data written to journalctl cause such problem…
I am on BTRFS.
Well, something is eating up your storage space. Maybe you need to prune some stuff. If you have any Snaps, FlatPaks or AppImages, those take up a lot of storage.
You probably have (too) many btrfs snapshots. Also, btrfs uses compression by default, and therefore, unpacking the updates and recompressing them requires that there be some additional free space.
No, this is normal for btrfs if you’re using subvolumes.
Unlike in zfs, btrfs subvolumes are not block devices, and so the block device associated with a subvolume in the output of df is the one that holds the entire btrfs filesystem. The btrfscommand does have its own version of df built in, though.