Ok all you MySQL geniuses, I have what I think is an easy question for the more experienced developers out there.

I'm building a franchise business site using LAMP. This back-office application will serve up to 1000 businesses, each with about 1000 customers to track.

My question is... should we pile all the information into one SUPER Database, OR spawn a smaller Database for each business then manage them from a sort of console?

A SUPER database will need EXTREME fault protection as so many businesses depend on it. Many smaller databases may have better fault protection BUT may be harder to manage?

Any advice? Experiences? Gottchas? LIMITATIONS?

Thanks for your help,
NiseIdea