Stack Monitor was an asynchronous server performance and health monitoring system. It was a windows service and continually checked the health and state of all server's under it's purview, storing the results of it's monitoring to a database for reporting in the Intellicare application. It used WMI queries to pull the state and performance counters from each server remotely.
Each server type had it's own configuration; for example, on SQL Server based systems, there were additional metrics pulled from these servers and from the database system itself that were not pulled from generic server systems.
To monitor health and report on performance metrics, a rules engine was built in to dynamically check the results of the WMI queries against a list of outliers that needed to be reported on. So for example, if a server's CPU stayed at 90% or higher for an extended period of time, an alert was sent to the administration team that owned that particular server so they could check the state of their server.