We can't really help until you tell us what's using the space. Could be databases, could be docker, could be logs.

I use... du -xh --max-depth 2 /var/ | sort -h

If you suspect that the issue is journald, you can use the following command to check how much space it is using:

journalctl --disk-usage

Rather than periodically running journalctl --vacuum-size=500 to free up space, you can just limit the journal by adding the following to a new file such as /etc/systemd/journald.conf.d/size.conf:

[Journal]
SystemMaxUse=512M

This will limit the journal from using more than 512MB. That said, if journald is filling up fast, then something is spamming your logs and you could run journalctl -a -f to get a sense of what is being written to your logs.

You can use du -sh to figure out what's using most of the space. Something along the line of:

sudo -i
du -sh /home /usr /var
du -sh /var/*
du -sh /var/log/*
# etc

If it's one of your log files (likely), you can run something like tail -n 100 /var/log/[culprit] or tail -F /var/log/[culprit] to see what is being flooded in this log file exactly. Then you can try to fix it.

Install ncdu, then sudo ncdu -x /var it'll tell you what is taking up space, then if you tell us, we can help you identify how to minimize it and keep it low.

There's probably some program that's filling up /var/log. Check that directory.

If I had to guess, I'd say it's probably snaps. I've had the same issue and they've slowly been taking up more and more of my space, often with new gnome snaps being installed but the old ones not removed.

Try "snap list" to see what's installed as snap

There's a way to figure out what is responsible for using up all of that space. A couple of ways, really. Here's the one I use, though: du -s -h -x /path/to/ | sort -h -r | head -n 10*

• du
  • -s - display only a total for each argument
  • -h - human readable values
  • -x - do not cross file systems (in case you have another directory tree mounted under /var, which'll complicate figuring out what's in there for this purpose)
• sort
  • -h - compare human readable numbers (e.g., 1G, 2T)
  • -r - reverse sort (biggest first)
• head
  • -n 10 (first ten lines or less)

See what's using the space. This will list any dirs using >100MiB:

sudo du -h -d 5 -t 100M /var

Do you know what takes up the space? Something like gdu or ncdu will help you analyze the problem.

I had the same problem on my PC. Journald was spamming PCI errors all the time and the disk was filling up quite quickly. I ended up disabling journald and rsyslogd and the problem was fixed. You can delete the log files, if you find them

Are you using docker on BTRFS?

Docker makes use of BTRFS snapshots, but it snapshots the whole volume. That means as other programs delete/rewrite files, the old copies still exist in the snapshot. I've ended up putting /var/lib/docker on it's own filesystem.

What is the filesystem type? If it's btrfs, maybe it's the snapshots.

20gb for a Linux workstation is embarrassingly tiny in 2023.... Hell it's barely passable for a phone