I've seen this issue posted addressed in previous thread, but not sure what came of it.
One of our Orion machines NetPerfmon process hangs at random times, maybe once every 3-5 days. Often the Polling Status icon stays green, and there's little indication that its stopped working, at least from the web interface. But running a sniffer clearly shows its no longer sending ICMP, etc.
In System Manager , Polling Status, the Packet Queue ICMP & SNMP outstanding climb to big numbers, and and then seems to freeze, and nothing changes except the clock timer.
Stopping NetPerfmon and restarting fixes it, but then Orion wants to go out and do Baseline again.
We have Orion v9.1 SP3