IBM AIX 7.1 – Common Problem 168 – 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

After a predictive failure event, lparstat reports fewer online processors than configured. Performance baselines no longer match production runbooks.

Environment & Reproduction

Occurs on Power systems where service processor flags a CPU for deconfiguration.

lparstat -i
oslevel -s
uname -a

Root Cause Analysis

Cause is firmware moving a CPU to guard list following thresholded errors; affected resource is removed from the LPAR partition.

Quick Triage

Confirm processor counts, deconfig list, and HMC event log.

lparstat -i

Step-by-Step Diagnosis

Capture deeper evidence to isolate the failure path.

lparstat -i
prtconf | head -n 60
errpt -a -j 369D049B | head
lscfg -vp | head
lsattr -El proc0

Solution – Primary Fix

Apply the proven primary fix in a controlled change window.

diag
lsmcode -A
update firmware via HMC
rmdev -dl proc1
cfgmgr

Solution – Alternative Approaches

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

dlpar -p $(hostname) -m add proc 1
chhwres -r proc --proceduretype add
lssyscfg -r lpar

Verification & Acceptance Criteria

Confirm the system meets acceptance criteria after the change.

lparstat -i
lscfg -vp | grep -i proc
errpt | head

Rollback Plan

Revert cleanly if regressions appear during validation.

rmdev -dl proc1
cfgmgr
lparstat -i

Prevention & Hardening

Reduce recurrence with monitoring and preventive tuning.

errnotify firmware events
schedule diag -d
lsmcode -A monthly

Related Errors & Cross-Refs

Related to predictive memory failures, SMT mode changes, and firmware level mismatches.

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 Hardware Management, lsmcode and diag references.