Good quick description of serverless backup.  From the website:

Serverless backup over SANs requires three major components:

• The backup application itself
• The Extended SCSI Copy Command standard
• A protocol-aware, intelligent SAN appliance that can recognize protocols from many heterogeneous systems and transmit data at high speeds to the tape and DLT libraries.

With serverless backup, the data flows across the SAN directly from the disk drive to the tape device, with no data moving through the server. The enterprise servers only need to host the backup application, and the backup application determines what needs to be backed up and sends the command to a "copy agent" embedded in an intelligent SAN appliance. The intelligent SAN appliance detects the source and destination parameters, retrieves the data from the storage devices, writes it to the tape or DLT libraries, and reports completion (or status) back to the backup application.

 

Equipment list of Linux cluster, connecting hardware, software, etc

Details of the Research and Academic Computing Computing cluster at Indiana University

We'd need the Helix server, Helix proxy, and Helix DRM.  This would let us design a full blown service.  We should base it on Windows servers and connect to a large, fast disk array.  For now, a single scale system would be fine with, say, 25 streams.