ii)If I have two Integration Servers and two Brokers running on the same machine, since Broker Monitor always runs on port 6850, I will have to use only one Broker Monitor. Should I expect any problems in using one broker monitor with two broker servers.
iii) The first pair of Integration Server/ broker is already installed and running. Do I have to shut down the broker and broker monitor before installing the second one. Or will the broker monitor automatically detect the presence of the second broker server after its installation?
The Broker Monitor is a process that monitors the health of the Broker Servers on a host. In the event that the Broker stops (e.g.: temporary power failure, etc) the Broker Monitor will restart it. This mechanism that has been in place for all Broker versions and is designed to ensure Broker uptime.
The installer will always only install a single Broker Monitor per host. If there are multiple Brokers on the machine, then by design the single Broker Monitor will monitor all of the Broker Servers on that host. This also applies to multiple versions: for example, if you install a 6.x Broker on the same host as an existing 4.x / 5.x Broker, the 6.x Broker Monitor will monitor both Broker Server versions. The Broker Monitor does not monitor Integration Servers.
The webMethods installer will detect a running Broker Monitor and do the right thing automatically (stop the existing Broker Monitor, remove it, and install a newer version).