FreeBSD 14 – periodic security scripts cause sustained high load – Fix & Prevention

📖 ~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

Load average climbs at predictable times, degrading interactive and API workloads.

Environment & Reproduction

Occurs when periodic security and integrity checks overlap with peak traffic windows.

top
cat /etc/crontab
ls -la /etc/periodic

Root Cause Analysis

Expensive scans run concurrently and saturate CPU or disk during business hours.

Quick Triage

Identify active periodic tasks and resource profile.

ps auxww | egrep 'periodic|security'
iostat -x 1
vmstat 1

Step-by-Step Diagnosis

Map cron schedule overlap and inspect script runtime duration.

grep -R periodic /etc/crontab /etc/cron*
time periodic security
lastcomm periodic | head

Solution – Primary Fix

Move heavy periodic tasks to off-peak windows and reduce unnecessary checks.

cp -a /etc/crontab /etc/crontab.bak
vi /etc/crontab
service cron restart

Solution – Alternative Approaches

Split tasks across hosts or enforce cputime and nice limits for maintenance jobs.

Verification & Acceptance Criteria

Load profile smooths out and scheduled maintenance completes within expected duration.

uptime
sa -m | head
mailq || true

Rollback Plan

Restore previous crontab schedule if maintenance coverage gaps are detected.

cp /etc/crontab.bak /etc/crontab
service cron restart

Prevention & Hardening

Use observability alerts for cron load spikes and enforce runtime budgets per maintenance script.

Related Errors & Cross-Refs

Related to swap pressure incidents and long-running filesystem integrity checks.

Related tutorial: View the step-by-step tutorial for freebsd-14.

View all freebsd-14 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

periodic(8), crontab(5), and FreeBSD operations handbook entries.