Ubuntu 22.04 LTS EXT4 Remounts Read-Only After I/O Errors

📖 ~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

Writes fail with read-only filesystem errors, causing service disruptions and application failures.

Environment & Reproduction

Observed on Ubuntu 22.04 LTS under disk errors or sudden power interruptions.

Root Cause Analysis

Kernel detects ext4 metadata inconsistency or I/O faults and remounts partition read-only for safety.

Quick Triage

Check dmesg for ext4 and block-device errors before attempting remounts.

Step-by-Step Diagnosis

Confirm mount flags and run SMART or block-level checks to assess disk health.

Solution – Primary Fix

Boot into maintenance mode, run fsck on affected partition, then reboot.

Solution – Alternative Approaches

Migrate data to new storage if SMART indicates imminent drive failure.

Verification & Acceptance Criteria

Filesystem mounts read-write and no new ext4 I/O errors appear in kernel logs.

Rollback Plan

Restore from snapshot backup if fsck cannot repair without data loss risk.

Prevention & Hardening

Enable SMART monitoring, UPS protection, and periodic filesystem health checks.

Related Errors & Cross-Refs

Related to disk full issues, controller faults, and abrupt VM host resets.

Related tutorial: View the step-by-step tutorial for Ubuntu 22.04 LTS.

View all Ubuntu 22.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Consult man fsck.ext4, smartctl docs, and Ubuntu storage troubleshooting.