Ubuntu 20.04 LTS RAID Array Degraded

📖 ~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

Storage redundancy is reduced, increasing risk of data loss and performance instability.

Environment & Reproduction

Appears after disk errors, controller events, or unexpected reboots during active write workloads.

Root Cause Analysis

Member device failure or metadata inconsistency causes md arrays to enter degraded mode.

Quick Triage

Check mdstat and SMART indicators, and identify failing members before rebuilding actions.

Step-by-Step Diagnosis

Correlate kernel logs, mdadm detail output, and disk health metrics to confirm replacement target.

Solution – Primary Fix

Replace failed drive, re-add array member, and monitor rebuild progress to completion.

Solution – Alternative Approaches

Use hot spares or migrate to mirrored cloud volumes where hardware replacement is constrained.

Verification & Acceptance Criteria

Array returns to clean state with expected sync completion and no read/write error growth.

Rollback Plan

Stop rebuild process and restore prior disk mapping only if replacement behavior is unsafe.

Prevention & Hardening

Enable proactive SMART monitoring and maintain tested spare replacement workflow.

Related Errors & Cross-Refs

Often connected to filesystem remount-readonly events and disk timeout warnings.

Related tutorial: View the step-by-step tutorial for Ubuntu 20.04 LTS.

View all Ubuntu 20.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Use mdadm operational references and Ubuntu storage reliability guidance.