The Tivoli Enterprise Monitoring Server collects performance data from monitored resources, preprocesses it, and then archives it in a central database. You need at least one Tivoli Enterprise Monitoring Server to be the HUB for your Tivoli Enterprise Portal environment.
Detailed configuration instructions are provided in the Tivoli® Monitoring in the IBM® Knowledge Center. Search for Configuring Tivoli Enterprise Monitoring Server on z/OS®. Also see section ‘Installing and configuring the hub Tivoli Enterprise Monitoring Server'.