Hi I am looking to release a website that will initially have large amounts of uploads from users. The first will be 65GB and the rest will probably be close to 1TB. They could happen simultaneously.

My question is what type of amazon server instance would be best for this? The website is just being released so the traffic wont be very high. I have been using a micro instance for development but it is time to launch and I need more power.

Should I use auto scaling and a load balancer to increase the number of instances when I need it or Will a small or medium instance do the trick?

If I do use auto scaling and load balancing how do I handle things like sessions and the database/file lookups? Does one instance become the primary instance and the rest become clones?