Disk Full Under /var Causes Service Failures

📖 ~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

When /var fills up on RHEL 7, yum, journald, and multiple services fail because logs and runtime data cannot be written.

Environment & Reproduction

Service startup errors, package transaction failures, missing logs, and repeated no space left on device messages.

Root Cause Analysis

Unbounded logs, core dumps, cached packages, or runaway application output under /var/log and /var/cache.

Quick Triage

Measure filesystem usage, identify largest paths, and verify systemctl status for affected services.

Step-by-Step Diagnosis

Use journalctl and service logs to map exactly when writes began failing and which units were impacted first.

Solution – Primary Fix

Inspect logrotate settings, yum cache footprint, and journald retention policies to identify persistent growth drivers.

Solution – Alternative Approaches

Free space safely, run yum clean all, rotate and compress logs, restart failed units, and confirm writes succeed.

Verification & Acceptance Criteria

SELinux labels should remain intact during cleanup. firewalld is not a direct factor unless remote log shipping is blocked.

Rollback Plan

Validate systemctl active states, ensure journalctl entries resume normally, and test application transactions end-to-end.

Prevention & Hardening

If cleanup removed needed files, restore from backups and apply targeted retention controls instead.

Related Errors & Cross-Refs

Set alerts on /var usage thresholds and enforce retention policy for logs, caches, and backups.

Related tutorial: View the step-by-step tutorial for rhel-7.

View all rhel-7 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Review RHEL storage and log management guidance for resilient capacity planning.