High CPU Usage by systemd-journald on Busy Hosts

📖 ~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

systemd-journald spikes CPU and overall host responsiveness declines under log-heavy load.

Environment & Reproduction

Excessive log volume, verbose services, or insufficient journald rate-limiting parameters.

Root Cause Analysis

Run: top, pidstat -p $(pidof systemd-journald) 1, and journalctl –disk-usage.

Quick Triage

Identify top noisy units using journalctl -u and evaluate log level settings in affected services.

Step-by-Step Diagnosis

Capture process-level CPU metrics and bursty log streams.

Solution – Primary Fix

Capture tuned journald settings and reduced CPU after restart.

Solution – Alternative Approaches

Set journald.conf values such as RateLimitIntervalSec and RateLimitBurst appropriately.

Verification & Acceptance Criteria

Reduce verbose application log levels and remove noisy debug output in production.

Rollback Plan

Restart journald: sudo systemctl restart systemd-journald and monitor CPU trend.

Prevention & Hardening

CPU usage stabilizes and required logs are still retained for operations and security.

Related Errors & Cross-Refs

Set log budgets per service and alert on abnormal message rates in monitoring stack.

Related tutorial: View the step-by-step tutorial for rhel-9.

View all rhel-9 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Revert journald rate settings if critical logs are being dropped unexpectedly.