Journal Logs Growing Until Disk Pressure

📖 ~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

Root filesystem fills gradually; journald consumes significant space and affects system stability.

Environment & Reproduction

Common on busy servers with verbose services and no explicit journal size limits.

Root Cause Analysis

Persistent logs accumulate due to default retention behavior and high event volume.

Quick Triage

Confirm disk pressure source before deleting arbitrary files.

Step-by-Step Diagnosis

Run `journalctl –disk-usage`, inspect `df -h`, and identify noisy units with `journalctl -u -n 200`.

Solution – Primary Fix

Set `SystemMaxUse`/`RuntimeMaxUse` in journald config, vacuum old logs, and restart `systemd-journald`.

Solution – Alternative Approaches

Forward logs to external collectors and reduce local verbosity for chatty services.

Verification & Acceptance Criteria

Journal usage remains within policy limits and disk free space stabilizes.

Rollback Plan

Revert journald config changes and restore previous retention settings if needed.

Prevention & Hardening

Define centralized logging policy and alert on disk/journal growth thresholds.

Related Errors & Cross-Refs

`No space left on device`, service restarts due to disk pressure, and log write failures.

Related tutorial: View the step-by-step tutorial for Ubuntu 26.04 LTS.

View all Ubuntu 26.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

`man journald.conf`, Ubuntu logging docs, and systemd journal best practices.