monline

"GlusterFS is a scale-out NAS file system developed by Gluster. It aggregates various storage servers over Ethernet or Infiniband RDMA interconnect into one large parallel network file system. GlusterFS is based on a stackable user space design without compromising performance. It has found a variety of applications including cloud computing, biomedical sciences and archival storage. GlusterFS is free software, licensed under GNU AGPL v3 license."

Sounds quite impressive.
Here're a few more links:
http://www.gluster.org/about/
http://www.gluster.com/products/glusterfs/

It remains to be seen whether the recent acquisition of Gluster Inc. (by Red Hat) interferes with the open-source product's development/availability or not.