Lack of Distributed Monitoring
When trying to monitor hundreds or thousands of hosts and services, only one Nagios server
might not be sufficient to handle many check loads. To improve performance scalability, users should
set up multiple Nagios servers. Moreover, some users may want to set up Nagios servers in multiple
locations for reliability purpose. Out-of-the-box Nagios is not capable of distributed monitoring. Such
requirements must be achieved with external tools like NSCA [19] and DNX [30]. NSCA provides a
channel to integrate passive alerts and check results from multiple Nagios machines. DNX is a modular
extension of Nagios that distribute load of Nagios checking processes to multiple remote servers.