Data Center Capacities

The design of the data center is dependent on the balance of two sets of capacities:

Data center capacities: Power, cooling, physical space, weight load, bandwidth (or connectivity), and functional capacities
Equipment capacities: The various devices (typically equipment in racks) that could populate the data center in various numbers

Depending on the chosen site of the data center, one of these sets of capacities will usually determine the other. For example, if the project scope includes a preferred amount of equipment capacity for the data center, the knowledge of the equipment requirements can be used to determine the size of the center, the amount of power and cooling needed, the weight load rating of the raised floor, and the cabling needed for connectivity to the network. In other words, the equipment will determine the necessary data center capacities. On the other hand, if the data center will be built in a pre-existing space, and this space has limitations for square footage, power, etc., this will determine the supportable equipment capacities. In other words, the data center size and in-feeds will determine how much equipment you can put in the data center.

Note

The project scope should include the budget limitations, and these numbers (though not discussed in this chapter) must also be considered .

A new method for designing a data center based on these capacities uses a calculating system called RLUs. The actual process of defining RLUs to determine the capacities of a data center boils down to careful planning. RLUs will assist you in turning the critical design variables of the data center into absolutes. The idea is to make sure the needs of each rack are met as efficiently as possible. RLUs tell you the limits of device requirements and, therefore, the limits of the data center itself. Knowing these limits, no matter how great or small, gives you complete control over the design elements.