We have 4 instances RAC on 22.214.171.124 and ASM.
In order to get the best performance I have below questions.
1. In theory how many instances can be added in RAC (11g)?
2. Practically how many instances can give best performance?
Note: I think after certain number of instances the performance will be flat, means no more performance benefit after a certain level.
Is there any already proved method with statistics to decide the same?