Project Hosting on Google Code is a web-based platform for open source development, providing mailing lists, an issue tracker, a source code repository, download areas, and so on. This talk will focus on a new version-control component of Project Hosting on Google Code: Mercurial backed by Bigtable. Mercurial/Bigtable is designed to scale over thousands of machines and use Bigtable’s replication to run over multiple datacenters. It is built to be able to host hundreds of thousands of open source projects. Come learn about Mercurial’s architecture, and how we’ve extended it to grow to “Google size”.