open hardware

• The servers themselves are 1.5U high, half again as high as the normal 1-U rack, Facebook executives said. That allows Facebook to build more space in the racks for cooling; the company used 60-mm fans to move more air with less power, they said. The racks are built on shelves, so they can be easily serviced.

Richard Fichera, an analyst at Forrester, claimed that the servers are divide into two categories: the Web tier, a high-power server that uses dual-socket, 8-core Xeon X5650 chips; and the Memcache tier, which uses less CPU, and more memory, and incorporates 8-core "Magny Cours" AMD processors, he said in a blog post. Each server can have up to 6 local disks.
The power supplies are more than 93 percent efficient, almost heard of in an industry where 90 percent efficiency is considered outstanding. For backup power, they use a modular 48V DC battery backup unit that supplies up to six servers through a DC-DC converter in each server. Each battery is connected via the network, so that the Facebook IT managers can monitor the health of the system.
http://www.pcmag.com/article2/0,2817,2383283,00.asp

• Why Open Hardware?

By releasing Open Compute Project technologies as open hardware, our goal is to develop servers and data centers following the model traditionally associated with open source software projects.
http://www.opencompute.org/