journald Logs: Retention, Size Limits and Queries

Sat, 20 Jun 2026 00:00:00 +0000

On a systemd-based VPS the journal is not a plain text file you can tail and forget — it is a structured, indexed binary store managed by systemd-journald, and left at its defaults it will quietly grow until it claims a slice of your disk you never agreed to give it. That structure is a feature, not an annoyance: every log line carries metadata — the unit that emitted it, the priority, the PID, a monotonic timestamp — so you can ask precise questions instead of grepping a wall of text. This guide covers the two things that matter most for a server you actually operate: keeping the journal's size under control, and querying it quickly when something breaks at 2 a.m.

Logrotate for Nginx and App Logs on a Linux VPS

Tue, 16 Jun 2026 00:00:00 +0000

 1/var/log/myapp/*.log {
 2 daily
 3 rotate 14
 4 compress
 5 delaycompress
 6 missingok
 7 notifempty
 8 create 0640 www-data adm
 9 sharedscripts
10 postrotate
11 systemctl reload myapp >/dev/null 2>&1 || true
12 endscript
13}

That single stanza is the whole job: it keeps two weeks of compressed application logs, never lets them grow without bound, and tells the app to reopen its log file cleanly after each rotation. Every directive in it earns its place, and getting one of them wrong — particularly the postrotate signal — is how a server ends up writing gigabytes into a "rotated" file nobody is reading. This guide explains the stanza line by line, applies the same pattern to nginx, and shows how to test a rule safely before it runs unattended at 3 a.m.

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journald Logs: Retention, Size Limits and Queries

Logrotate for Nginx and App Logs on a Linux VPS