Take a look at SQL alternatives. There's an interesting PostgreSQL use case which uses only open source tools to achieve a good horizontal scaling solution. This post tells a little about how they did it: http://highscalability.com/skype-plans-postgresql-scale-1-billion-users The post also says that there is a very similar approach using MySQL.

I'm been thinking for some time about moving to Canada. Though, I'm a little afraid of the Brazilian reputation outside Brazil (don't think it's very good). I'm mainly a database architect (work with PostgreSQL), but also a *nix developer. Does someone here has something to say about experiences working with or hiring people from Brazil?