Yes, it is called DGit for Distributed Git:
As many readers already know, Git itself is distributed—any copy of a Git repository contains every file, branch, and commit in the project’s entire history.
DGit uses this property of Git to keep three copies of every repository, on three different servers. The design of DGit keeps repositories fully available without interruption even if one of those servers goes down.

DGit automatically selects the servers to host each repository, keeps those replicas in sync, and picks the best server to handle each incoming read request. Writes are synchronously streamed to all three replicas and are only committed if at least two replicas confirm success.
GitHub now stores repositories in a cluster called github-dfs—dfs
is short for “DGit file server.” The repositories are stored on local disks on these file servers and are served up by Git and libgit2. The clients of this cluster include the web front end and the proxies that speak to users’ Git clients.
