Ceph is a system daemon which publishes a reliable distributed block storage, also published as an S3-compatible object storage API via a proxy.

There is a Ceph Cluster in a LAN maintained by allmende.io for circus.dev.

Interesting use cases are (1) as a backend for Deis and (2) as a transparent, "scale-out" NAS via CephFS.

Also see Ceph on Raspberry Pi 2 and Gigabit networking for Raspberry Pi 2 for ways to work around Ethernet and USB 2.0 I/O deficiencies.