IBM AIX 7.2 – Common Problem 165 – 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

Processes are killed by the kernel with paging-space-low events. Application teams report random crashes during overnight reporting jobs.

Environment & Reproduction

Occurs on LPARs running memory-heavy workloads with single small paging space.

lsps -a
oslevel -s
uname -a

Root Cause Analysis

Cause is psize threshold breach. AIX kills processes when paging space approaches full to protect the kernel.

Quick Triage

Check paging usage and trends, ensure swap layout meets best practice.

lsps -a

Step-by-Step Diagnosis

Capture deeper evidence to isolate the failure path.

lsps -a
svmon -G
vmstat 2 5
errpt -j C5C09FFA | head
ps -ealf | sort -nrk6 | head

Solution – Primary Fix

Apply the proven primary fix in a controlled change window.

chps -s 4 hd6
mkps -s 4 -n rootvg
vmo -p -o npswarn=8192
vmo -p -o npskill=4096

Solution – Alternative Approaches

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

smitty pgsp
mkps -s 4 -n datavg
swapon -a

Verification & Acceptance Criteria

Confirm the system meets acceptance criteria after the change.

lsps -s
svmon -G
vmstat 1 5

Rollback Plan

Revert cleanly if regressions appear during validation.

rmps paging01
chps -d 1 hd6
lsps -a

Prevention & Hardening

Reduce recurrence with monitoring and preventive tuning.

errnotify -a 'en_name=pagingspace'
topasrec -L
nmon -c 60

Related Errors & Cross-Refs

Related to memory leaks in applications, vmo tuning mistakes, and high computational page pressure.

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 AIX 7.2 Performance Management chapter on paging.