Syslog defines severity levels from to . Lower numbers mean more severe.
Emergency. System is unusable.
Alert. Immediate action needed.
Critical. Hardware failures.
Error. Failed operations.
Warning. Something might fail soon.
Notice. Normal but significant events.
Informational. Status updates.
Debug. Verbose troubleshooting.
Most production devices should log at level or . Use debug only when troubleshooting. Debug generates enormous volume.