Alias for FATAL
Log everything. Not a level.
Critical conditions. Example: Application component unavailable, unexpected exception
Detailed debug information
Emergency: system is unusable
Runtime errors that do not require immediate action but should be logged and monitored
Action must be taken immediately. Example: Entire website down, database unavailable, etc This should trigger the SMS alerts and wake you up
Interesting events
Normal but significant events
Trace information
Exceptional occurrences that are not errors (Use of deprecated APIs)
Alias for WARN
List of Levels