The Server Alert Log makes it possible for system administrators and installation technicians to trace activities in the server. The Server Alerts are categorized into a set of predefined categories which individually can be turned on or off. Examples are logging of Deployment activities, Errors occuring in the business logic and User Authetication attempts that fails.
For a complete list and description of the Server Alert Log Categories see the documentation described in Server Alert Log Categories
The actual logging result is monitoring in Solution Manager Server Alert Log.