What makes this project different from Nagios?
In addition to Nagios, people often ask about OpenNMS as compared to another large non-commercial network management project, Big Brother. To discuss Big Brother first, their “Better than Free” license does not really qualify as a true open source license like the GNU GPL that both OpenNMS and Nagios are published under, so it can’t really be considered in a comparison. This is not to discount the large Big Brother user community – if it works for you, great – but true open-source community-based developement is different from freeware/shareware. As far as Nagios is concerned, the main difference is that OpenNMS was developed from the beginning to be an enterprise-grade solution capable of monitoring a theoretically unlimited number of devices (via a distributed and tiered system). This is even alluded to with respect to SNMP datacollection in the Nagios documentation: Note: Nagios is not designed to be a replacement for a full-blown SNMP management application like HP OpenView or Open
