Yves Rubin has written the NSClient addon for monitoring NT servers. The addon includes a service that runs on your NT/2000 servers and a plugin that gets executed from the Nagios host. The NSClient addon is capable of monitoring the following items:
- CPU Load
- Disk Usage
- Service States
- Process States
- Memory Usage
- File Age
- Most Perflib counters
You can find the NSClient addon at http://nsclient.ready2run.nl/.
The good news is that NT has a lot of performance data that you can monitor. The bad news is that its difficult to do. Your best bet is probably going to be to install SNMP services on all your NT boxes.
In order to expose NT performance counters for monitoring, you'll have to run the SNMP service on all servers you want to monitor. You'll also have to install any necessary performance MIBs for the services you want to monitor. I believe these can be found in the NT Resource Kit or in various server admin packages. If you've feeling extra lucky you can try to search the Microsoft site for the terms SNMP and MIB and maybe you'll find something...
You can search the MRTG mailing list archives for more information on configuring NT servers to expose various performance counters via SNMP. I know this has been discussed in the past, as many people are graphing various NT performance statistics using MRTG. In fact, somebody from Microsoft is actually doing it - you can find their web page at http://snmpboy.msft.net/.
Once you've actually got the SNMP stuff working, you can use the check_snmp plugin to query your NT servers and generate alarms.