java memory is managed by JVM and JVM has no intrinsic knowledge on tenants, which are pega business artifacts. Of course, the more tenants you have, the more likely that bigger heap/perm memory is required, but there is no simple formula. There are so many factors that can affect memory utilization. Also, RAM is different from heap, but RAM should be bigger than the heap as native memory (besides the reserved heap for java process) is needed for other non-java processes. The only way to profile the memory is to run realistic use cases on the server and monitor the memory usage.

Thanks for your response Kevin. Based on the information you provided:

1) When a tenant is added, memory is allocated to that tenant from the heap/permgen that the JVM has to work with

2) The available heap/permgen will run out at some point when enough tenants have been created

3) Memory must be analyzed as tenants are created to determine at what point Java heap/permgen will run out.

That begs the question, "What tool should be used to analyze the Java heap/permgen so I can determine at what point the server will run out of memory?"

You could use AES(Autonomic Event Services) to moitor the memory consumed by your application. AES is capable of more than just monitoring the system memory.  Alos AES provides standard reports that can be leveraged.

A good read about AES can be found here https://pdn.pega.com/about-autonomic-event-services-aes-enterprise-edition/about-autonomic-event-services-aes-enterprise

Hope this helps!