Saw at osnews today a reference to Zumastor which is at: http://zumastor.googlepages.com/

Zumastor is a community project started by Google members to bring enterprise storage features to Linux. Currently, we offer a ready-to-use network storage server with enterprise features such as online volume backup, multiple volume snapshots, remote volume replication, integration with Kerberized CITI NFS and Samba, all wrapped up with a nice, easy management interface.

As a subproject we offer the ddsnap virtual snapshot Linux kernel extension, which adds multiple snapshot and remote replication capability to Linux filesystems in general.