Amazon Relational Database Service (Amazon RDS) (beta)

[eluser]theseamusjames[/eluser]
When our site crashed the other day, we had a consultant come in and give us some direction. He explained it like this:

When you're getting a lot of traffic, two things are affect the processing power. First, each apache request - be it for the page, the css, the js, the images, whatever - impacts load. Second, the requests from the DB affect load. Hence, when we were getting killed the other day, it wasn't the 2500 apache requests were getting every minute, but also the multiple DB requests we make for each of those actions. Hence, running the DB on a separate server from the the apache server, you greatly increase your ability to process responses. Moreover, RDS allows you to setup Master/Slave read hierarchies, so handle spikes in load.

From a security perspective, I guess the biggest part is partitioning your data away from your publicly visible web host. If someone were to gain root access to your EC2 server, they wouldn't necessarily have access to your data. Additionally, RDS has some great backup support, so if you do lose something, your not down for long.