FreeBSD 15: UFS requires fsck after unclean power loss

📖 ~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

Boot enters maintenance mode and affected filesystems remain unavailable until integrity checks complete.

Environment & Reproduction

Triggered by abrupt shutdown, controller reset, or virtualization host interruption.

Root Cause Analysis

Pending metadata writes leave journal and filesystem state inconsistent at next mount attempt.

Quick Triage

Identify impacted mounts and confirm no underlying hardware failure before fsck repair.

Step-by-Step Diagnosis

Run safe filesystem diagnostics and inspect boot logs for repeated consistency faults.

Solution – Primary Fix

Execute controlled fsck repair and remount filesystems with post-check validation.

Solution – Alternative Approaches

Restore from snapshot or backup when structural corruption exceeds safe automated repair limits.

Verification & Acceptance Criteria

System boots normally and filesystem reports clean state without recurring consistency errors.

Rollback Plan

Unmount and revert to latest recoverable backup if repair introduces application-level issues.

Prevention & Hardening

Improve power resilience, UPS policy, and graceful shutdown orchestration during maintenance.

Related Errors & Cross-Refs

Associated with write cache settings and unstable storage backplane events.

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

fsck_ufs man page, UFS tuning guides, and FreeBSD storage reliability recommendations.