– Tate Cantrell, chief technology officer of Verne Global (www.verneglobal.com), says:

The Green Grid (www.thegreengrid.org) has said in the past that the point for measurement of the IT Equipment Power is at the distribution point upstream of the computer equipment at the computer room power distribution units (PDU’s). For most companies, this means at the output circuit breaker at the upstream breaker panel. Google (http://www.google.com/corporate/green/datacenters/measuring.html) on the other hand has encouraged the industry to take the power measurement at the input to the server, excluding even the power cords of the computers in the IT Equipment Power measurements.

Google goes further to encourage data center managers to choose the utility side of their substation when calculating the Total Facility Power for the PUE calculation. This is a bit more specific and a little more challenging than the Green Grid definition of at or near the facility’s Utility power meter.

The well-run enterprise has a goal to increase top line revenue while keeping costs in check and preferably reducing costs over time. The purpose of the data center is to improve worker productivity within the enterprise. With proper direction, improved worker productivity should improve top line revenues. By improving on metrics, data center managers can impact the enterprise by improving worker productivity and thereby top line revenues, while honing efficiency and delivering the data center solutions with reduced cost impact to the organizations.

Without metrics, a manager cannot monitor the ongoing performance of the data center operation. And without a well designed set of metrics that are customized to the infrastructure at hand, a data center manager is unable to properly predict the trends of a data center and will be unable to effectively time projects for capacity increase.