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Table of contents
Symptom & Impact
IBM AIX 7.3: HACMP/PowerHA cluster split-brain after network loss can interrupt LPAR workloads and risks SLA breach if AIX admins do not act on the PowerHA split-brain signal quickly.
Environment & Reproduction
Reproduce on IBM AIX 7.3 LPARs by triggering the PowerHA split-brain 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 PowerHA split-brain on AIX 7.3.
Quick Triage
Run safe checks first: errpt -a, lssrc -a, lsps -a, df -g, and topas snapshot before changing any PowerHA split-brain configuration.
Step-by-Step Diagnosis
Use AIX command-line tools (lsdev, lscfg, lsattr, lsvg, errpt, snap) to confirm the PowerHA split-brain root cause and document state.

Solution – Primary Fix
Apply the least-disruptive PowerHA split-brain remediation using cfgmgr, chdev, smitty, or installp; reload services and confirm errpt is clean.
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Solution – Alternative Approaches
If the primary PowerHA split-brain 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 PowerHA split-brain 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 PowerHA split-brain.
Prevention & Hardening
Prevent PowerHA split-brain recurrence with TL/SP hygiene, NIM-driven patching, monitoring thresholds in nmon/topas, and runbooks.
Related Errors & Cross-Refs
Track related PowerHA split-brain 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 PowerHA split-brain remediation guidance.
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