Discourse image and installation size. Clean /var/lib/docker/overlay2?

I’d be interested to know how much your 15G server costs, and from which supplier. My 25G machine costs me $6 per month from Digital Ocean, and my 20G machine costs $3 from Hetzner.

If you don’t expect to have to debug any behaviour from system logs, you can be very brutal in pruning the journals.

# journalctl --rotate
# journalctl --vacuum-time=1s

although what I’ve done is change the policy:

/etc/systemd/journald.conf:
[Journal]
SystemMaxUse=50M

The disk usage on the 20G machine, which has a very small low-activity forum on it, is like this:

# df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/sda1        19G  9.9G  8.1G  56% /

operating system:

15M /bin
16M /sbin
43M /boot/
135M /var/cache/
223M /var/log
435M /lib
464M /var/lib/apt
1.1G /usr
2.1G /swapfile
4.3G total

discourse:

# du -hs /var/discourse/ /var/lib/docker/
1.5G /var/discourse/
7.5G /var/lib/docker/

edit: aha, but we’re double-counting, see instead

# du -hxs /var/discourse/ /var/lib/docker/
1.5G /var/discourse/
4.1G /var/lib/docker/

the forum itself, within the above:

201M	/var/discourse/shared/standalone/uploads
315M	/var/discourse/shared/standalone/postgres_data
930M	/var/discourse/shared/standalone/backups

I’m running Ubuntu 18.04 whereas it looks like you’re running something more like 20.04 which is probably bigger.