Ubuntu 20.04 LTS – multipathd causes delayed boot on single-disk VM – Fix & Prevention

📖 ~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 process stalls for extended time while waiting for nonexistent multipath devices.

Environment & Reproduction

Common on cloud VMs inheriting generic images with multipath enabled by default.

Root Cause Analysis

multipathd probes storage patterns not present in single-disk environments, adding timeouts.

Quick Triage

Confirm boot delay points to multipath units using systemd-analyze blame output.

Step-by-Step Diagnosis

Inspect initramfs modules, multipath config, and udev logs for probe delays.

Solution – Primary Fix

Disable or tune multipath on single-path hosts and rebuild initramfs.

Solution – Alternative Approaches

Keep multipath enabled only on hosts attached to SAN or redundant block devices.

Verification & Acceptance Criteria

Boot duration improves and no required storage devices are missing post-change.

Rollback Plan

Re-enable prior multipath configuration if storage path requirements change.

Prevention & Hardening

Align base images with platform storage topology before fleet rollout.

Related Errors & Cross-Refs

Can accompany initramfs timeout messages and delayed root device discovery.

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

Ubuntu multipath and initramfs configuration documentation.