IBM AIX 7.2 – Common Problem 095 – 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

rmss has reduced effective memory and was not reset after testing.

Environment & Reproduction

Triggered when a sizing exercise ends without rmss -r being run.

Root Cause Analysis

Kernel simulates a smaller memory footprint, hurting performance.

Quick Triage

Run rmss -p to see the current simulated memory size.

Step-by-Step Diagnosis

Check lsattr -El sys0 -a realmem versus rmss -p output.

Solution – Primary Fix

Reset with rmss -r to return to physical memory size.

Solution – Alternative Approaches

Alternative: reboot the LPAR if rmss state is corrupted.

Verification & Acceptance Criteria

Verify rmss -p matches lparstat -i installed memory after the reset.

Rollback Plan

Capture rmss -c and -p results for ticket history.

Prevention & Hardening

Document rmss usage windows in change control to avoid forget-cases.

Related Errors & Cross-Refs

Related: poor paging and unexpected svmon -G values.

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: rmss memory sizing tool.