Facebook has release the v1.0 Open Rack specification according to a blog post by Peter Bratach on its website. The new specification documents the evolution of the Open Rack over the last few months since the 0.5 version was published:
• Exclusive focus on a single column rack design.
• Higher inlet temperature of 35°C, which reflects other Open Compute designs and real-world data center temperatures.
• Network switches that can be deployed in various configurations, not just above the topmost power zone.
• Compute chassis are 1xOpenU – 10xOpenU high, and are supported on L-shaped brackets that directly snap into the vertical structural rack posts. These brackets, installable without tools, can be mounted at 0.5xOpenU (24mm) increments.
• Maximum height is dictated by the size of the power zone, but heights above the suggested maximum of 2100mm should be given closer scrutiny for stability.
• Innovative clips easily mate the chassis power connectors to the bus bars.
The Open Rack is the first rack design to diverge from the existing 19-in. rack standard, which had its origins in the railroad industry and was later adopted by the recording industry, among others. The 537 mm width (about 21 in.) of the chassis has a lot of practical engineering benefits, like improved airflow, greater energy efficiency, and better volumetric efficiency, as there is more space used for IT equipment instead of just air and metal.
The rack itself is 600mm wide, which makes it the same as the overall width of a 19-in. rack, so it fits into existing data centers worldwide.