I've got a better handle on this now, but cannot seem to make use of multiple instances. I've created four instances (didn't realize this had to be done manually - the only way?), but the total max connections that I'm able to achieve when testing is the maximum amount per instance. I've got memory concerns so really want to make use of multiple instances instead of more workers/connections on a single instance. Here are my current settings:
Max Worker Processes = 3
Max Connections = 4
Worker Load Factor = 5%
Instance Load Factor = 25%
Start Count = 4
This should result in a max of 48 total connections, 12 per instance. When I shut down all instances and start adding browser connections, I can see that all of the 4 instances are indeed started, but after 12 connections I can't add any more (503 error). Any thoughts on why I can't seem to make use of my 4 instances?
Determining when another worker would be started:
Max # of Concurrent connections per worker * Worker Load Factor
50 * 5% = 2.5 (meaning the 3rd Browser Connection would add another worker up to the Max worker processes)
Determining when another Application Instance would be started:
Max # of connections per worker * Max worker processes * Instance Load Factor
50 * 3 * 50% = 75 (meaning the 76th connection would cause an additional instance to be started)