Proper way to use log Severity Levels: TRACE, DEBUG, INFO, ERROR, and FATAL

There are many different views on log levels. However, the model presented below is something I encountered at one of my previous jobs, and it seemed to be the most practical in real-world application.

• TRACE - for tracking problems and debugging only.
• DEBUG - diagnostic information for non-developers, such as an SRE admin.
• INFO - general useful information related to the state of the system. For example, logging the start, stop of a daemon, or configuration changes.
  This is the level admins usually set by default to avoid receiving too many logs but still keep track of all important events.
• WARNING - issues that resolved automatically and remained unnoticed by the user.
  For example, a user uploads an image, we couldn’t save it to one disk but tried saving it to another and succeeded.
• ERROR - errors visible to the user that couldn’t be resolved automatically. For example, the uploaded image couldn’t be saved on the server.
• FATAL - critical errors that lead to the system being halted to prevent data loss or corruption.