I've used OpenNMS to monitor a number of different systems while doing three different jobs. My first installations (using 1.2.something) were inside a development platform for web hosting, which became a live platform and subsequently also monitored several hundred other hosts and devices managed by the same company. We used it as a backstop for an existing Nagios system which it eventually superseded. These systems were monitoring DNS, web and mail hosting servers providing services to several hundred thousand users with in excess of a million domains - knowing quickly that we had a problem was essential to our daily lives!
Nowadays I use the 1.7 branch for a similar role (again with Nagios being run by a different team) because I find it far easier to make OpenNMS do what I need it to do.
Community support for OpenNMS is an essential part of the package and I hope, in some small way, to continue to make use and contribute to that community. Keep up the good work!
- Graeme Fowler, Loughborough University, plus PIPEX Communications/Host Europe PLC before that, UK