This may also tangentially help, to understand if a logging request (from the code) at a certain level will result in it actually being logged given the effective logging level that a deployment is configured with. Decide what effective level you want to configure you deployment with from the other Answers here, and then refer to this to see if a particular logging request from your code will actually be logged then...
For examples:
- "Will a logging code line that logs at WARN actually get logged on my deployment configured with ERROR?" The table says, NO.
- "Will a logging code line that logs at WARN actually get logged on my deployment configured with DEBUG?" The table says, YES.
from logback documentation:
In a more graphic way, here is how the selection rule works. In the following table, the vertical header shows the level of the logging request, designated by p, while the horizontal header shows effective level of the logger, designated by q. The intersection of the rows (level request) and columns (effective level) is the boolean resulting from the basic selection rule.
So a code line that requests logging will only actually get logged if the effective logging level of its deployment is less than or equal to that code line's requested level of severity.