Are there any guidelines or limitations on how many agents should be managed from a single SC server? I understand a lot depends on frequency of scheduling but was wondering if there any quidelines or hard limitations.
Since a given SC config can only have one agent meaning a backup involves 1 agent there are no limitations, you could have 1000s of agents. The scServer will never talk to more than one agent at a single point in time within a config. It was designed this way to avoid scalability issues
One area we caution against is backups against the same agent/host. The scAgent in 3.3.0 is single threaded and can only handle one response at a time, it will queue everything else. This means that if you run the same backup config or backup configs at same time that hit same agent/host you will run into timeout issues due to excessive queueing. The workaround in 3.3.0 is to increase the timeout or run multiple agents on a host which also isn't great since it means multiple ports. In SC 3.4.0 the next release we are adding option to start agent in multi-threaded mode but there are some limitations like it isn't supported and wont work on windows and with our domino and mysql plugins.