It depends of what you are trying to do. About the database : Cache. Offer a different flow that does not need the database, like with hardcoded stuff. Etc etc

It depends of what you are trying to do. About the database : Cache. Offer a different flow that does not need the database, like with hardcoded stuff. Etc etc About doubling the costs : It highly depends. On a small app, sure it may double the cost. On a big thing with thousands of servers, you can play a bit more with redistributing roles and all.