Ubuntu 16.04 LTS – swap not enabled 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 escalates quickly and processes are killed due to absent swap.

Environment & Reproduction

Common when swap UUID changes or fstab entries are invalid after storage work.

Root Cause Analysis

Swap device cannot be found or activated during boot sequence.

Quick Triage

Check swapon status, fstab references, and current memory pressure levels.

Step-by-Step Diagnosis

Validate swap device presence and review boot logs for activation failures.

Solution – Primary Fix

Repair swap mapping, reactivate swap, and persist configuration changes.

Solution – Alternative Approaches

Provision swapfile with tuned vm settings when partition swap is unavailable.

Verification & Acceptance Criteria

Swap is active after reboot and memory spikes no longer trigger premature OOM events.

Rollback Plan

Restore prior swap configuration if performance degrades under new setup.

Prevention & Hardening

Monitor swap activity and maintain validated boot-time memory configuration baselines.

Related Errors & Cross-Refs

Failed to activate swap and OOM-killer events are frequently correlated.

Related tutorial: View the step-by-step tutorial for Ubuntu 16.04 LTS.

View all Ubuntu 16.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

See Linux memory management and Ubuntu swap administration documentation.