title: Is it better to have multiple databases vis-a-vis multiple instances on Amazon RDS?
body: <p>I am planning to deploy my web application (ASP.Net based) on the Amazon EC2 and the persistence on Amazon RDS. I have a 'gut feeling' that at least my session store (again on RDS) should be separate from the rest of the application database. This is because I am expecting high activity in the session store. </p>
  
  <p>RDS supports the ability to create multiple databases on single instance. However, I would like to know if it would be wise to take a separate instance or whether a separate database is good enough. I know that it is somewhat pre-mature to expect such a scalability need, but this is more from planning perspective, because it may disruptive to switch the session state server for a running application later. </p>
  
  <p>Further, 1 more point to note is that having 2 small instances looks to be cheaper that scaling up a small instance to a large (it is 4 times to be precise). And to finish, are there any recommended practices already available for planning (for cloud database)?</p>