IBM AIX 7.3 – Common Problem 169 – 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

Client LPARs lose access to virtual disks after a VIOS upgrade. VG vary-off occurs and applications time out.

Environment & Reproduction

Affects single VIOS configurations or paired VIOS where one path is unstable.

lspath
oslevel -s
uname -a

Root Cause Analysis

Cause is mismatched VTD configuration or NPIV WWPN reassignment after a VIOS code update.

Quick Triage

Validate paths from client and VIOS sides.

lspath

Step-by-Step Diagnosis

Capture deeper evidence to isolate the failure path.

lspath
lsdev -Cc disk | head
lsvg
echo 'lsmap -all' | ssh padmin@vios1
echo 'ioslevel' | ssh padmin@vios1

Solution – Primary Fix

Apply the proven primary fix in a controlled change window.

rmdev -Rdl hdisk5
cfgmgr -l vscsi0
importvg datavg hdisk5
varyonvg datavg

Solution – Alternative Approaches

Use these alternatives when the primary fix is blocked by environmental constraints.

chdev -l fcs0 -a num_cmd_elems=2048 -P
shutdown -Fr
resvg

Verification & Acceptance Criteria

Confirm the system meets acceptance criteria after the change.

lspath -F 'name path_id status' | head
lsmap -all (VIOS)
lsvg datavg

Rollback Plan

Revert cleanly if regressions appear during validation.

rmdev -Rdl vscsi0
cfgmgr
importvg -L datavg

Prevention & Hardening

Reduce recurrence with monitoring and preventive tuning.

VIOS HA pair documentation
updateios -accept
backupios -file /backup/vios1.bk

Related Errors & Cross-Refs

Related to MPIO PCM mismatches, NPIV zoning errors, and dual-VIOS heartbeat loss.

Related tutorial: View the step-by-step tutorial for aix-7.3.

View all aix-7.3 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

IBM PowerVM VIOS documentation, lsmap and chdev references.