Where Does journald Store Config and Logs?
journald config lives in /etc/systemd/journald.conf with logs under /var/log/journal. Set Storage=persistent to keep boots.
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journald splits config from storage. Settings live in journald.conf with drop-ins beside it. Logs live in /var/log/journal when persistence is on, in memory when it is not.
Volatile is the default that surprises people. Fresh boots with empty history mean Storage was never set persistent. One line plus a restart fixes it permanently.
Where systemd-journald stores this, by platform
/etc/systemd/journald.conf
Storage, rate limits, and retention knobs. Drop-ins in journald.conf.d override it. Restart the service after edits.
/var/log/journal
Binary journal files per boot when persistent. Query with journalctl, vacuum with journalctl flags.
Frequently asked questions
Why do logs vanish after reboot?
Set Storage=persistent in journald.conf and restart systemd-journald. Logs then land in /var/log/journal and survive reboots. volatile keeps only the current boot.
How do I cap journal disk usage?
Run journalctl --vacuum-size=500M or --vacuum-time=14d. Rate limits and caps live in the same conf file that governs retention.
How do I read logs for one service?
Query with journalctl -u name, -b for this boot, --since for ranges. No log files to grep by hand, the journal indexes everything.
Notice an outdated path? Let us know.