XtreemFS: A Distributed & Replicated File-System
Phoronix: XtreemFS: A Distributed & Replicated File-System
While EXT4 and Btrfs are the most talked about file-systems on Phoronix, there are certainly many more out there, especially when it comes to distributed file-systems and those largely only targeting enterprise environments. One example is XtreemFS, which is an open-source file-system that is distributed with support for clients and servers from any location and connected together using the Internet. This GPLv2-licensed file-system is also meant to easily replicate data across data-centers to reduce latency and network traffic...
I don't know about this XtreemFS but AFS does this and is proven.
Recent versions of AFS have improved greatly check them out AFS is also multi platform.
http://www.openafs.org/ try the 1.6 series its much improved over previous releases.
http://www.secure-endpoints.com/ also combine it with kerberos for single sign on across the entire network be it your home or in my case my school its pretty slick.