Phabricator does not currently have a comprehensive backup system, but creating backups is not particularly difficult. We will share an approach to automate backups and save them onto Dropbox. We don't like to think about what might happen, but its always good to have some backups.
Phabricator can host Git, Mercurial and Subversion repositories. It also works well with existing repositories (like GitHub, Bitbucket, or other repositories you already have elsewhere) without needing to host them itself.
Phabricator is an open source collection of web applications which makes it easier to scale software companies. It is currently available as a continuous release.