In the Nagios area Reporting are different analysis functions, these give an overview over complete availability of various systems and system groups. With the collected system states a trend analysis can be completed. This is helpful when an extension of one system is necessary. In addition to the monitoring functions Nagios has other functions that can affect complete availabilty.
So the following scene: An Apache web server is inspecting the functions by Nagios. This item is performed in a defined periodical period of time of two minutes. In the Nagios configuration of this service is defined that application testing maximum fail two times then following procedures are induced by Nagios. Before notification about ressource failure "Apache web server" another operation can be planned. This could be the try to restart the service. Does this step fail a notification is send to a responsible contact.