IBM AIX 7.1 – Common Problem 021 – 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

Latency doubles after Service Pack install and nmon shows higher syscall counts.

Environment & Reproduction

IBM AIX 7.2 LPAR exhibiting performance regression after SP issues under standard PowerVM workloads.

instfix -i | head
nmon -F /tmp/nmon.log

Root Cause Analysis

Tunable defaults reset by SP cause IO/VMM regressions.

Quick Triage

Confirm scope with errpt, recent changes, and subsystem state via lssrc.

lppchk -v
no -L | head

Step-by-Step Diagnosis

Compare pre/post nmon and ioo/no settings against baseline.

ioo -L
schedo -L | head

Solution – Primary Fix

Restore tunables from saved baseline and re-test workload.

no -p -f /etc/tunables/nextboot
ioo -p -f /etc/tunables/nextboot

Solution – Alternative Approaches

Roll back to previous bos.rte level via alt_disk clone.

Verification & Acceptance Criteria

Confirm subsystem returns to RUNNING state and errpt shows no new entries.

vmstat 2 5
nmon -F /tmp/nmon2.log

Rollback Plan

Restore prior configuration from mksysb or alt_disk_install clone if the fix regresses.

alt_rootvg_op -W -d hdisk1  # wake clone with old SP

Prevention & Hardening

Encode the fix in NIM customisation scripts and monitor via topas/nmon.

smit tunable  # baseline tunables in /etc/tunables/

Related Errors & Cross-Refs

schedo regression; ioo MAX_PBUF

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

AIX Performance Management