IBM AIX 7.2 – Common Problem 101 – 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

errpt repeatedly logs DISK_ERR4 entries and I/O latency climbs.

Environment & Reproduction

Aging SAS disks or flapping MPIO paths on Power LPARs running AIX 7.2.

Root Cause Analysis

Underlying hdisk reports SCSI sense data captured by errdemon/diagela.

Quick Triage

Run errpt | head and inspect lspath -l hdiskN for Failed paths.

Step-by-Step Diagnosis

Use errpt -aN hdiskN to capture sense bytes, timestamps and resource names.

Solution – Primary Fix

Replace the failing disk or recover the path with chpath -s disable then -s enable.

Solution – Alternative Approaches

Migrate the logical volume off the disk first with migratepv hdiskN hdiskM.

Verification & Acceptance Criteria

errpt no longer logs recurring DISK_ERR entries and iostat latency returns to baseline.

Rollback Plan

Re-enable the original path with chpath -s enable if the swap was a false positive.

Prevention & Hardening

Enable diagela monitoring and schedule errclear with retention policies.

Related Errors & Cross-Refs

Often paired with FSCSI_ERR2 or LVM_SA_QUORCLOSE entries in the same window.

Related tutorial: View the step-by-step tutorial for aix-7.2.

View all aix-7.2 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

IBM Docs: errpt, diag, MPIO administration on AIX 7.2.