Typical deployment diagram

http://bit.do/dgeXm EdrawSoft secret sale page.
What you are seeing now is the typical deployment diagram of an application as you can see you have a load balancer behind that is the web server farm. You have a cache server farm also mentioning about distributed caching so it become extremely important to be able to increase your memory of your cache as well. Hence it is advisable to go for a cache server farm again you have a lot of caching technologies like windows (( )) or MEM cache which very easily would allow you to do that, you don't have to write you own caching technology and again application layer is load balanced and you could also see that the data base is being sharded so that's one thing can do it you could shard your database to have multiple servers to handle the load.