📖 ~1 min read
Table of contents
Symptom & Impact
Expected kernel behavior does not change after reboot.
Environment & Reproduction
Often due to file placement errors or quoting syntax mistakes.
Root Cause Analysis
Tunable is set in the wrong context or overridden by later loader files.
Quick Triage
Compare runtime sysctl state with kenv and loader file entries.
Step-by-Step Diagnosis
Trace all definitions and check boot logs for parse failures.
Solution – Primary Fix
Place valid tunable key/value in loader.conf and reboot.
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Solution – Alternative Approaches
Use sysctl.conf for runtime-adjustable values instead of loader tunables.
Verification & Acceptance Criteria
Post-reboot kenv and runtime values match intended settings.
Rollback Plan
Remove recent loader entries and reboot to baseline.
Prevention & Hardening
Separate boot-time tunables from runtime sysctl policy.
Related Errors & Cross-Refs
May overlap with securelevel and read-only boot media constraints.
Related tutorial: View the step-by-step tutorial for FreeBSD 13.
View all FreeBSD 13 tutorials on the Tutorials Hub →
Browse all common problems & solutions on the Tutorials Hub.
References & Further Reading
loader.conf and sysctl manual references.
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