After operating Big Sister for a while you will notice that it is not very hard to add newly monitored systems. However, if you remove healt checks on agent-side the entries on the server side are not automatically disappearing since the Big Sister server does not know if the status reports disappeared accidentally or intentionally.
In order to remove a single health check for one host, follow the following procedure
remove the health checks in the uxmon-net of the agent that was responsible for performing the test
wait until the agent re-read its configuration (up to one minute) or re-start the agent
execute
bsadmin -d localhost remove host.check
on the Big Sister server side (of course, host and check must be replaced by the actual host and check names)
after up to one minute the status lamp in the row check of the host host will disappear on the server display
In order to remove a whole host with all its checks, follow this procedure
remove all the tests in the uxmon-net files of the agents that were responsible for performing the tests
wait until the agents re-read their configuration (up to one minute) or re-start the agent
remove all group associations for the host in bb-display.cfg on the server side
wait until the server re-read its configuration or re-start the server
execute
bsadmin -d localhost leave host \*
on the Big Sister server side
after up to one minute the machine will disappear