Your app should be clustered, and your db (where your state should live) can be clustered too. Ultimately you want as little state in your app servers as possib

Your app should be clustered, and your db (where your state should live) can be clustered too. Ultimately you want as little state in your app servers as possible, since this makes it harder to scale them out, reboot them etc. That's the ideal case anyway, its hard to avoid session state with websockets etc, but you can still push a lot down to the database layer