IBM AIX 7.3 – Common Problem 189 – 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

IBM AIX 7.3: nmon high CPU steal time on shared LPAR can interrupt LPAR workloads and risks SLA breach if AIX admins do not act on the CPU steal signal quickly.

Environment & Reproduction

Reproduce on IBM AIX 7.3 LPARs by triggering the CPU steal path; capture errpt entries, alog output, and exact timestamps for evidence.

Root Cause Analysis

Primary cause is typically ODM drift, device or filesystem state, or a stale runtime resource tied to CPU steal on AIX 7.3.

Quick Triage

Run safe checks first: errpt -a, lssrc -a, lsps -a, df -g, and topas snapshot before changing any CPU steal configuration.

Step-by-Step Diagnosis

Use AIX command-line tools (lsdev, lscfg, lsattr, lsvg, errpt, snap) to confirm the CPU steal root cause and document state.

Solution – Primary Fix

Apply the least-disruptive CPU steal remediation using cfgmgr, chdev, smitty, or installp; reload services and confirm errpt is clean.

Solution – Alternative Approaches

If the primary CPU steal fix is blocked, use alt_disk_copy, multibos, or NIM-based rollback paths with documented trade-offs.

Verification & Acceptance Criteria

Acceptance requires clean errpt, healthy lssrc subsystems, restored CPU steal functionality, and no repeat predictive errors.

Rollback Plan

Keep an AIX rollback path ready: mksysb image, alt_disk_copy clone, bosboot validation, and ordered subsystem restart for CPU steal.

Prevention & Hardening

Prevent CPU steal recurrence with TL/SP hygiene, NIM-driven patching, monitoring thresholds in nmon/topas, and runbooks.

Related Errors & Cross-Refs

Track related CPU steal signatures in errpt and PowerHA logs to speed triage of future AIX 7.3 incidents.

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

Use IBM AIX 7.3 documentation, IBM Support flashes, and internal postmortems for deeper CPU steal remediation guidance.