IBM AIX 7.2 – Common Problem 170 – 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

Backups using JFS2 snapshots fail and the parent filesystem reports errors. Subsequent writes to the parent LV stall.

Environment & Reproduction

Affects filesystems where internal or external snapshots exist without sufficient reserved space.

snapshot -q /appdata
oslevel -s
uname -a

Root Cause Analysis

Cause is snapshot copy-on-write area exhaustion; JFS2 invalidates snapshots when reserve runs out.

Quick Triage

Identify active snapshots and reserve usage.

snapshot -q /appdata

Step-by-Step Diagnosis

Capture deeper evidence to isolate the failure path.

snapshot -q /appdata
lsfs -q /appdata
lsvg -l datavg
df -g /appdata
errpt | head

Solution – Primary Fix

Apply the proven primary fix in a controlled change window.

snapshot -d /dev/snap_appdata
chfs -a snap=+1G /appdata
backup -f /tmp/appdata.bk /appdata
snapshot -o snapfrom=/appdata -o size=1G

Solution – Alternative Approaches

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

rmsnap -d snap_appdata
recreate snapshot with larger size
schedule outside peak hours

Verification & Acceptance Criteria

Confirm the system meets acceptance criteria after the change.

snapshot -q /appdata
lsfs -q /appdata
df -g /appdata

Rollback Plan

Revert cleanly if regressions appear during validation.

snapshot -d /dev/snap_appdata
chfs -a snap=-1G /appdata
mount -a

Prevention & Hardening

Reduce recurrence with monitoring and preventive tuning.

errnotify snapshot loss
monitor reserve via cron
backup nightly

Related Errors & Cross-Refs

Related to inline log corruption, NIM-backed backups, and Tivoli Storage Manager integration.

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 JFS2 snapshot guide, snapshot and chfs man pages.