IBM AIX 7.3 – Common Problem 53 – 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

Cannot create files: ‘No space left on device’ but df shows free space.

Environment & Reproduction

JFS2 filesystem with many small files exhausting inode allocation.

Root Cause Analysis

JFS2 nbpi (bytes-per-inode) too high for workload.

Quick Triage

Run df -i /mountpoint and compare IUsed vs IFree.

Step-by-Step Diagnosis

Use istat and find /fs -xdev -type f | wc -l to confirm inode pressure.

Solution – Primary Fix

Recreate FS with crfs -a nbpi=4096 or expand with chfs -a size=+1G.

Solution – Alternative Approaches

Move data to a new FS with rsync and remount original.

Verification & Acceptance Criteria

df -i shows IUse% well below 100% after expansion.

Rollback Plan

Restore from mksysb or NIM backup if recreation fails.

Prevention & Hardening

Size nbpi at FS creation based on average file size.

Related Errors & Cross-Refs

JFS2 log-full, fs full despite df showing space.

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

AIX JFS2 administration guide on nbpi tuning.