Operations Manager 2007 Product Team blog recently released a couple posts about some issues you may be seeing in that product. In case you missed them I have some info and links below:
1. Grayed out healthy agent icon
Recently we have been receiving some questions on the meaning of the 'grayed-out, Healthy' agent status icon (see picture below).
You will see this in the Monitoring space in the Computers view and the Discovered Inventory view and the Operations Manager ==> Agent ==> Agent Health State view. In short, the grayed-out icon means that the health service watcher on the RMS that is watching the health service on the monitored machine is not receiving heartbeats from the agent anymore. It had been receiving them previously (and it was reported as healthy), but now it is not. This also means that the management servers are no longer receiving any information from the agent at all.
To continue reading see http://blogs.technet.com/momteam/archive/2008/08/01/grayed-out-healthy-agent-icon.aspx
2. You may need to update the agent restart threshold on Exchange 2007 Servers Managed by Operations Manager 2007
The Operations Manager 2007 Management Pack tracks memory usage of the MonitoringHost.exe process via the private bytes counter. By default, the agent will be automatically restarted if memory usage for MonitoringHost.exe is above 100MB. On large Exchange 2007 systems, this threshold may be too low. The recommended threshold is 600MB.
This is why:
On Exchange 20007 servers the .Net runtime (CLR) gets loaded into MonitoringHost.exe. The way Windows performance counters work is that to read a performance counter from an application a DLL provided by that application is loaded into the process. Since some of the Exchange services (for example Hub Transport) are written in managed code, the CLR performance counter client is loaded into the MonitoringHost.exe process for reading those counters. The .net runtime performance counter client implementation loads the CLR to handle reading the counters from the managed service.