Disk Full Under /var on RHEL 9

📖 ~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

The /var filesystem reaches 100 percent usage, causing service failures and package operation errors.

Environment & Reproduction

dnf, journald, and application writes fail with no space left on device.

Root Cause Analysis

Runaway logs, core dumps, cache growth, container layers, or temporary files not rotated.

Quick Triage

Use df -h, du -x -h /var | sort -h, and journalctl –disk-usage to locate top consumers.

Step-by-Step Diagnosis

Purge safe cache locations and vacuum journals with retention limits.

Solution – Primary Fix

Repair logrotate/app retention policies and restart affected services.

Solution – Alternative Approaches

After space is freed, restart failed units with systemctl and verify write paths.

Verification & Acceptance Criteria

If moving data paths, restore SELinux contexts so services can write correctly.

Rollback Plan

Confirm stable free space over time and successful transaction/log writes.

Prevention & Hardening

Restore removed data only from vetted backups if cleanup was overly aggressive.

Related Errors & Cross-Refs

Set alerting thresholds and enforce retention for logs, dumps, and container artifacts.

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

df -h; du -x -h /var; journalctl –vacuum-time=7d