Swap Not Activating After Storage Layout Change

📖 ~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 because swap is inactive.

Environment & Reproduction

Partition or LV changes performed without updating swap references.

Root Cause Analysis

Swap UUID mismatch or missing mkswap signature.

Quick Triage

Run swapon –show and systemctl status swap.target.

Step-by-Step Diagnosis

Compare blkid output with /etc/fstab and inspect boot logs for swap errors.

Solution – Primary Fix

Create swap signature, update fstab UUID, and activate with swapon -a.

Solution – Alternative Approaches

Use swapfile on dedicated filesystem when partitioning is constrained.

Verification & Acceptance Criteria

swapon –show lists expected device and memory pressure stabilizes.

Rollback Plan

Restore prior swap config and deactivate new swap target.

Prevention & Hardening

Validate swap activation in post-change runbooks.

Related Errors & Cross-Refs

Failed to activate swap /dev/…, dependency failed for swap.target.

Related tutorial: View the step-by-step tutorial for oracle-linux-10.

View all oracle-linux-10 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

swapon, mkswap, and fstab administration manuals.