Open Rack

Open Rack is an Open Compute Project standard for a rack and power delivery architecture as an efficient, scalable alternative to the EIA-310 19-inch rack.^[1] It is designed specifically for large-scale cloud deployments.

There are several key design features intended to make equipment more efficient to deploy, support, and operate:

• The power to all of the compute, storage, or network devices is supplied by a pair of busbars located in the rear of the rack. The bus bars are supplied with 48 V DC by a shelf of power supplies, which provides efficient conversion from the local (usually three-phase) AC mains supply.
• The IT equipment that fits into Open Rack is 21 inches or 533 millimetres wide. This is a 15% increase in frontal area that provides more airflow to the IT devices, helping data centers to reduce cooling costs. The vertical spacing is also taller, to accommodate better airflow and enclosures with improved physical designs that do not sag and interfere with adjacent equipment.
• All cables and interconnects are accessed from the front of the rack and the IT equipment is hot-pluggable and serviceable from the front of the rack. Service personnel no longer access the rear of the rack or need to work in the hot aisle.

Open Rack rack units are called OpenU or just OU.

An Open Rack consists of three modular zones: power, equipment, and cable.

To maintain compatibility with existing server infrastructure, OU cabinets are the same 24-inch (610 mm) external width as conventional server cabinets. However, an OpenU is slightly taller, to improve airflow and cable management.

An equipment bay is 21 inches or 533 millimetres wide. An equipment bay rests on support shelves and blind-mates with the power supply through busbars.

• Reference specifications and designs
• Rack & Power section of Open Compute Project website