IBM AIX 7.1 – Common Problem 232 – Diagnosis and Fix

📖 ~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

lspath shows Missing paths and SAN-backed disks throw transient I/O errors.

Environment & Reproduction

Occurs after SAN switch failover, zone change, or HBA firmware mismatch on POWER LPARs.

Root Cause Analysis

MPIO loses one or more fcsN paths, leaving the disk with reduced redundancy.

Quick Triage

Run lspath, lsdev -Cc adapter, and fcstat fcsN to spot Missing paths and link errors.

Step-by-Step Diagnosis

Inspect errpt -aj LINK_ERR and SC_DISK_ERR entries to confirm adapter or fabric issues.

Solution – Primary Fix

Re-enable paths with chpath -s enable -l hdiskN -p fcsN after the fabric is restored.

Solution – Alternative Approaches

If the path stays Missing, rmpath then cfgmgr to rediscover the device cleanly.

Verification & Acceptance Criteria

lspath reports Enabled on all paths and fcstat shows no link errors for 1h.

Rollback Plan

Disable problematic paths with chpath -s disable and reroute I/O via remaining HBAs.

Prevention & Hardening

Keep HBA firmware on supported levels and zone each LPAR to redundant fabrics.

Related Errors & Cross-Refs

Related to disk hardware errors, syncvg stale partitions, and SAN switch logs.

Related tutorial: View the step-by-step tutorial for aix-7.1.

View all aix-7.1 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

IBM AIX 7.2 MPIO and Fibre Channel adapter administration docs.