Two questions about Logon Group

Question

About logon group, it describes as below in the help.sap.com.
1. Each SAP application has different resource requirements. Certain applications may therefore require more servers and logon groups. For example, you should assign separate servers for the application component PP.
Q1: How a certain application use more than one servers via logon group, and how it use sap memory which resides in different servers?
2. If it is not practical for you to assign separate servers to integrated applications, such as the application components SD-MM and FI-CO, you should assign common logon groups to these applications.
Q2: I don't understand this sentence exactly.
Thanks so much.
James

Answer 1

Not sure if I exactly understood what your problem is, but let me give it a try:
A1: One logon group may have several servers attached to it. If users user1, user2, user3, ... are going to connect to the logon group, they will be sent to different servers. None of those users will be able to use memory from more than one server. But, let's say user1 and user2 will use resources from server1, whereas user3 will use resources from server2. The goal is that all servers will have the same (or similar) load, just by distributing users.
A2: If it is not possible to have four logon groups for the four applications SD, MM, FI, CO, but you still want different logon groups, then, at least, you should create two logon groups, one for SD and MM, the other one for FI and CO. That's because resource requirements are similar for SD and MM, and for FI and CO.
hope this helps