Journalctl can accumulate a lot of system logs over time being, we can clear the logs using --vacuum-time or --vacuum-size argument.
Only retain last 3 days of logs:
journalctl --vacuum-time=3dOnly retain 1 GB of logs:
journalctl --vacuum-size=1GYou can configure the max log size in /etc/systemd/journald.conf:
SystemMaxUse=1GThen restart the journald service:
systemctl restart systemd-journald