Ubuntu 14.04 LTS Swap Not Activating After Reboot

📖 ~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

Memory pressure increases rapidly and OOM kills occur without active swap.

Environment & Reproduction

Appears after disk cloning, partition changes, or stale fstab UUID entries.

Root Cause Analysis

Swap partition or file reference in fstab no longer matches actual block device.

Quick Triage

Check swapon –show, /etc/fstab entries, and blkid output.

Step-by-Step Diagnosis

Validate swap signature, UUID mapping, and boot logs for swap activation errors.

Solution – Primary Fix

Recreate swap signature if needed, update fstab, and activate with swapon -a.

Solution – Alternative Approaches

Deploy dedicated swapfile with controlled size and persistence settings.

Verification & Acceptance Criteria

Swap appears active after reboot and memory pressure tests complete without OOM.

Rollback Plan

Revert fstab and disable new swap target if unexpected performance regressions appear.

Prevention & Hardening

Validate fstab UUIDs after storage changes and monitor swap activity continuously.

Related Errors & Cross-Refs

Connected to kswapd spikes, OOM killer events, and degraded application responsiveness.

Related tutorial: View the step-by-step tutorial for Ubuntu 14.04 LTS.

View all Ubuntu 14.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

swapon/fstab manuals, Ubuntu memory management notes, and performance tuning docs.