Clear systemd journal

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Mattias Geniar, February 26, 2018

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On any server, the logs can start to add up and take considerable amount of disk space. Systemd conveniently stores these in /var/log/journal and has a systemctl command to help clear them.

Take this example:

$ du -hs /var/log/journal/
4.1G    /var/log/journal/

4.1GB worth of journal files, with the oldest dating back over 2 months.

$ ls -lath /var/log/journal/*/ | tail -n 2
-rw-r-x---+ 1 root systemd-journal 8.0M Dec 24 05:15 user-xxx.journal

On this server, I really don’t need that many logs, so let’s clean them out. There are generally 2 ways to do this.

Clear systemd journals older than X days

The first one is time-based, clearing everything holder than say 10 days.

$ journalctl --vacuum-time=10d
Vacuuming done, freed 2.3G of archived journals on disk.

Alternatively, you can limit its total size.

Clear systemd journals if they exceed X storage

This example will keep 2GB worth of logs, clearing everything that exceeds this.

$ journalctl --vacuum-size=2G
Vacuuming done, freed 720.0M of archived journals on disk.

Afterwards, your /var/log/journal should be much smaller.

$ du -hs /var/log/journal
1.1G    /var/log/journal

Saves you some GBs on disk!

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