Quickly inspect and control how much disk space the systemd journal consumes, and reclaim space without breaking logging. 16.11.2025 | reading time: 2 min System logs can quietly eat disk space; check the systemd journal size and learn how to trim it safely with concrete commands you can run right now. Measure current footprint Start with a single command to see the journal footprint and a quick example output: ``` journalctl --disk-usage Archived and active journals take up 1.8G in the file system. ``` That's all you need to know the current consumption before making changes. Reclaim space now You can vacuum logs by size, time, or number of files; examples and typical outputs follow: ``` sudo journalctl --vacuum-size=200M Vacuuming done, freed 1.6G ``` ``` sudo journalctl --vacuum-time=2weeks Vacuuming done, removed journals older than 2 weeks ``` ``` sudo journalctl --vacuum-files=5 Vacuuming done, left 5 journal files ``` Set persistent limits Make limits permanent by editing `/etc/systemd/journald.conf` and setting keys such as SystemMaxUse, SystemKeepFree, and RuntimeMaxUse; example snippet: ``` # /etc/systemd/journald.conf SystemMaxUse=200M SystemKeepFree=50M RuntimeMaxUse=50M ``` After editing run `sudo systemctl restart systemd-journald` to apply changes. Extra checks and integrity Verify journal integrity and inspect locations with these commands and outputs: ``` journalctl --verify PASS: /var/log/journal/… ``` ``` sudo du -sh /var/log/journal 1.8G /var/log/journal ``` Also check the journald service status with `systemctl status systemd-journald` to see runtime behavior. When volatile vs persistent matters Logs live in memory under `/run/log/journal` when not persistent and on disk under `/var/log/journal` when persistence is enabled; enabling persistence moves logs to disk and increases visibility across reboots, so pair that change with size limits. Safe practices Prefer vacuuming during maintenance windows, keep backups of critical logs if needed, and combine journald limits with external log aggregation for long-term retention to avoid accidental data loss. Next steps Mastering journal control is small but practical; continue by automating checks in scripts, forwarding logs to a collector, and studying systemd logging deeper to prevent incidents and save disk space. Join Bits & Bytes Academy First class LINUX exam preparation. filesystem utilities storage troubleshooting
