FreeBSD 13 Redis Warning About vm.overcommit Causes Background Save Failures

📖 ~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

RDB/AOF persistence operations fail, increasing data loss risk.

Environment & Reproduction

Triggered under memory pressure during BGSAVE.

redis-cli info persistence

Root Cause Analysis

Insufficient memory headroom for fork-based persistence operations.

Quick Triage

Check memory usage, dataset size, and persistence cadence.

redis-cli info memory

Step-by-Step Diagnosis

Correlate Redis warnings with host memory/swap state.

sysctl vm.stats.vm.v_free_count && swapinfo -h

Solution – Primary Fix

Lower maxmemory pressure and tune save policy to fit host capacity.

redis-cli config set save '900 1 300 10'

Solution – Alternative Approaches

Use replica offload for persistence or move to AOF-only with careful fsync policy.

Verification & Acceptance Criteria

BGSAVE completes reliably with no repeated memory warnings.

Rollback Plan

Restore previous Redis config and restart service.

Prevention & Hardening

Maintain memory headroom budget for fork events.

Related Errors & Cross-Refs

Related to swap thrash and latency spikes under load.

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

View all freebsd-13 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Redis persistence and memory tuning references for BSD systems.