IBM AIX 7.1 – Common Problem 161 – 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

Backup and reporting cron jobs no longer execute. No errors appear immediately but downstream systems miss expected files.

Environment & Reproduction

Occurs when the cron daemon is stopped, crontab format is invalid, or user is in /var/adm/cron/cron.deny.

lssrc -s cron
oslevel -s
uname -a

Root Cause Analysis

Cause is one of: cron not running, crontab parse error, or restricted user list excluding the account.

Quick Triage

Verify cron status, crontab syntax, and access lists.

lssrc -s cron

Step-by-Step Diagnosis

Capture deeper evidence to isolate the failure path.

lssrc -s cron
ps -ef | grep cron
crontab -l
cat /var/adm/cron/cron.deny
ls -l /var/adm/cron/log

Solution – Primary Fix

Apply the proven primary fix in a controlled change window.

stopsrc -s cron
startsrc -s cron
crontab -l > /tmp/root.cron
crontab /tmp/root.cron

Solution – Alternative Approaches

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

rm /var/adm/cron/cron.deny
echo root > /var/adm/cron/cron.allow

Verification & Acceptance Criteria

Confirm the system meets acceptance criteria after the change.

lssrc -s cron
tail /var/adm/cron/log
crontab -l

Rollback Plan

Revert cleanly if regressions appear during validation.

stopsrc -s cron
startsrc -s cron
crontab -r

Prevention & Hardening

Reduce recurrence with monitoring and preventive tuning.

errnotify -a 'en_name=cron'
logrotate-equivalent for /var/adm/cron/log
audit setup

Related Errors & Cross-Refs

Related to /var fill events, syslog misconfiguration, and shell PATH errors in cron jobs.

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

IBM AIX 7.2 Commands reference for cron and crontab.