What is the root logger in log4net

I don't quite understand what the main functionality for root logger as shown in following section is. What is the difference from other loggers?

<root>
  <level value="WARN" />
  <a开发者_Python百科ppender-ref ref="RollingLogFileAppender" />
</root>

I think the log4net documentation explains this quite nicely:

Loggers are organized in hierarchies. E.g.: The logger Foo.Bar is child of the logger Foo. This way the loggers create a tree and the root logger is simply the root of that tree (in the example Foo is a child of the root logger).

This hiearchy allows for some interesting configuration applications (e.g. disable/enable logging for an entire sub system of your application).

The Root Logger can hold a list of appenders and settings (typically just the log level) used when logging.

Check this link for more details about the Root Logger with Log4net.