Facebook showed  working prototype of Open Rack, an energy efficient server that’s intended to power data centers which can theoretically scale to more than 100,000 physical machines.

OpenRack is very much a work in progress. The current rack uses Facebook’s third and so-far most compact generation of a two-socket x86 server. Engineers here already envision a fourth generation that shrinks the server design  yet again. Ideally, the board would contain only processors and a PCI Express fabric, no Ethernet or other components—but that will require a variant of Express that is only on the drawing board today.

  • Each OpenVault tray has control electronics on a slide-out board. In future, the board could host an ARM-based controller to handle special storage functions. Facebook believes such an application could become its first use of an ARM SoC.
  • Specifically, they expect to move from 250-500 Gbyte hard drives—the smallest they can now get—to 128 Gbyte  serial ATA SSDs which have enough capacity and might even be cheaper.

Each OpenRack slot can fit three of these latest, third-generation designs of a two socket x86 server.

Facebook’s second-gen server design was larger, so only two fit in a single rack tray

Up to seven power supplies fit in a single OpenRack, supporting up to 12.6 kW per rack.

Facebook hardware design manager Amir Michael shows how two-socket server sleds slide into an OpenRack.

A single tray in the OpenVault storage design houses a 3 x 5 array of hard disk drives.