Some minutes ago my computer crashed because apparently my hard drive was full. After booting in recovery mode I then found out that my syslog file in /var/log was 64GB large. I saved the end of the file on another partition and then deleted it. Apparently docker seems to have been the problem because I found a lot of this at the end of the file and there was a docker process running at 200% CPU the whole time. After clearing the log and killing docker everything seems to be normal.
Nov 15 01:44:08 Elemental docker.dockerd[1120]:
time="2019-11-15T01:44:08.727060251Z" level=error
msg="failed to get event" error="rpc error: code =
Unavailable desc = all SubConns are in TransientFailure, latest connection
error: connection error: desc = \"transport: Error
while dialing dial unix /run/containerd/containerd.sock:
connect: permission denied\"" module=libcontainerd namespace=plugins.moby
Nov 15 01:44:08 Elemental docker.dockerd[1120]: time="2019-11-15T01:44:08.727116701Z"
...
And so on. I hope this problem won't appear again but still I would like to know what might have happened here.