Debian 13 – Swap disabled after reboot causing memory pressure – Fix & Prevention

📖 ~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

High memory pressure triggers OOM kills because swap is inactive.

Environment & Reproduction

Happens after UUID changes, fstab edits, or resized disks.

Root Cause Analysis

Swap device/file is missing or fstab entry points to wrong UUID/path.

Quick Triage

Check swap signatures and current fstab mapping.

Step-by-Step Diagnosis

Validate swap file/device permissions and activation attempts during boot.

Solution – Primary Fix

Recreate or remap swap and ensure persistent fstab entry.

Solution – Alternative Approaches

Create a swap file if dedicated partition is unavailable.

Verification & Acceptance Criteria

Swap is active after reboot and memory pressure improves.

Rollback Plan

Disable newly created swap and restore previous fstab configuration.

Prevention & Hardening

Include swap checks in post-boot validation and capacity monitoring.

Related Errors & Cross-Refs

Often linked to OOM events and overcommitted container hosts.

Related tutorial: View the step-by-step tutorial for Debian 13.

View all Debian 13 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Debian memory management and swap configuration documentation.