I have a web application written in asp.net mvc2. Currently hosted on amazon cloud ec2. Because of growing traffic we want move multi instance enviorenment. I have a custom session class which currently initiate at session start (global asax) and i am using via getter or setter class in application. Because of multi instance chore i have to handle hole security architecture. I am looking a better way to handle this problem.

I am looking for good implementation of session and how to apply on amazon ec2 multi instance environment. What is road blocks for system architecture?