Purpose of Rack Location Units

The job of planning the data center is one of balancing. You will add equipment, modify the in-feeds based on the equipment, find the limits to the feeds, reevaluate the equipment population or configuration, find that the budget has changed, then reevaluate equipment and resources.

The Rack Location Unit (RLU) system is a completely flexible and scalable system that can be used to determine the equipment needs for a data center of any size , whether 100 or 100,000,000 square feet. The system can be used whether you are designing a data center that will be built to suit, or using a predefined space. The RLU determinations are a task of the design process and can determine whether or not the space is adequate to fulfill the company requirements. Regardless of limiting factors, RLUs allow you the flexibility to design within them.

Flexibility is the key.

In a data center, most devices are installed in racks. A rack is set up in a specific location on the data center floor, and services such as power, cooling, bandwidth, etc., must be delivered to this location. This location on the floor where services are delivered for each rack is generally called a "rack location." We also use the information on these services as a way to calculate some or all of the total services needed for the data center. Services delivered to any rack location on the floor are a unit of measure, just like kilos, meters , or watts. This is how the term "rack location units" was born.

RLUs are defined by the data center designer based on very specific device requirements. These requirements are the specifications that come from the equipment manufacturers. These requirements are:

• Power (how many outlets/circuits it requires, how many watts it draws)

• Cooling (BTUs per hour that must be cooled)

• Physical space (how much floor space each rack needs, including the cooling dimensions)

• Weight (how much a rack weighs)

• Bandwidth (how it connects to the network)

• Functional capacity (how much computational power, physical memory, disk space, as well as how many spindles, MFLOPS, database transactions, and any other measures of rack functions)

RLUs based on these specifications can be used to determine:

• How much power, cooling, bandwidth, physical space, and floor load support is needed for the racks, alone, in groups, and in combination with other racks

• How many racks and of what configurations the data center and outside utilities can support

Unlike other methods , the RLU system works in both directions: determining necessary resources to accommodate and feed the equipment, and assisting changes in the quantities and configurations of the equipment to accept any limitation of resources.