Having a personal forge means I don't really have to care about scalability. It runs with the embedded SQLite engine just fine. No need for a complex setup with a separate database. Small is better :) I currently have 17 repositories in it, some of them are mirrors from GitHub repos, some are simple repos with Jekyll sources for my websites. I have all the repos also on my laptop and my home server, so even if everything explodes, I can restore everything I need.