Digital Downloads and Scale

Hello everyone, I'd appreciate any insights, or source suggestions regarding site traffic and necessary adjustments. For example, I'm using a simple digital download page for an indie artist. Not a ton of traffic, not a ton of concurrent requests. Was thinking about introducing something similar for a bigger artist(though still not huge) and I'm concerned for any trouble more demand might create. On the web server side, I'm not worried, as it's on a Pair high volume account. I am concerned where I might need back-ups or adjustments to code and database queries. Not quite sure where to start in researching this - any ideas or keywords would be appreciated. Thanks, -dg