Ubuntu 24.04 LTS – systemd journal grows too large – Fix & Prevention

📖 ~1 min read

Table of contents

1. Symptom & Impact
2. Environment & Reproduction
3. Root Cause Analysis
4. Quick Triage
5. Step-by-Step Diagnosis
6. Solution – Primary Fix
7. Solution – Alternative Approaches
8. Verification & Acceptance Criteria
9. Rollback Plan
10. Prevention & Hardening
11. Related Errors & Cross-Refs
12. References & Further Reading

Symptom & Impact

Disk usage increases rapidly and root partition fills with journal logs.

Environment & Reproduction

Seen on busy hosts with verbose services and no journal size policy.

journalctl --disk-usage
df -h /var/log
systemctl status systemd-journald

Root Cause Analysis

No retention limits allow persistent journals to grow unchecked.

Quick Triage

Measure journal growth and verify current journald settings.

grep -E 'SystemMaxUse|RuntimeMaxUse' /etc/systemd/journald.conf
journalctl --disk-usage

Step-by-Step Diagnosis

Inspect high-frequency units and log priority mix.

journalctl -p warning -b -0 | tail -n 100
systemctl list-units --state=failed
sudo du -h /var/log/journal | sort -h | tail

Solution – Primary Fix

Vacuum old logs and configure persistent size limits.

sudo journalctl --vacuum-size=500M
sudo sed -i 's/^#SystemMaxUse=.*/SystemMaxUse=500M/' /etc/systemd/journald.conf
sudo systemctl restart systemd-journald

Solution – Alternative Approaches

Forward logs to rsyslog or external collector to reduce local retention pressure.

sudo apt install -y rsyslog
sudo systemctl enable --now rsyslog

Verification & Acceptance Criteria

Journal size stays within configured limits.

journalctl --disk-usage
sudo systemctl status systemd-journald

Rollback Plan

Restore previous journald.conf and restart service.

sudo cp /etc/systemd/journald.conf.bak /etc/systemd/journald.conf
sudo systemctl restart systemd-journald

Prevention & Hardening

Monitor log growth and alert before partitions become critical.

journalctl --disk-usage
df -h

Related Errors & Cross-Refs

Related to debug logging left enabled in production services.

Related tutorial: View the step-by-step tutorial for Ubuntu 24.04 LTS.

View all Ubuntu 24.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

systemd-journald and Ubuntu logging documentation.