Swap Exhaustion and Memory Pressure on Busy Hosts

📖 ~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

Performance collapses, swap usage spikes, and processes are killed under load.

Environment & Reproduction

Memory leak, oversized worker pools, or insufficient RAM/swap sizing.

Root Cause Analysis

Run top -aSH, swapinfo -h, and vmstat 1 to identify pressure patterns.

Quick Triage

Reduce workload concurrency and restart offending services to reclaim memory.

Step-by-Step Diagnosis

Track heavy consumers with top -o res and confirm swap trends via swapinfo -h.

Solution – Primary Fix

Inspect application config for excessive workers and check system logs for OOM-like events.

Solution – Alternative Approaches

Tune service limits, add swap if needed, and schedule capacity upgrades.

Verification & Acceptance Criteria

Verify sustained low paging rates and stable response times after tuning.

Rollback Plan

Set memory dashboards and alerting on swap growth and page faults.

Prevention & Hardening

Revert aggressive tuning changes and restore previous service parameters.

Related Errors & Cross-Refs

Escalate when kernel panics or repeated memory starvation persists despite tuning.

Related tutorial: View the step-by-step tutorial for freebsd-15.

View all freebsd-15 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

swapinfo -h; top -aSH; vmstat 1; service restart