Planning Your Data Center Capacity Needs
As you plan for your computing demands for the coming years, most IT Managers focus on planning for growth and refreshing applications, servers, storage and network components. An equally important, but often over looked factor, is the actual data center facility itself, which houses, powers, cools, and secures the valuable contents of your IT infrastructure. Blade and unified computing, while offering many benefits, have definitely resulted in an increase of watts per cabinet to effectively power and cool them. A typical data center ten years ago may have functioned at 75 watts per square foot, allowing for a maximum of about 3kw / rack maximum, based on an aggressive 25 square feet / rack made possible with the popular 24-inch rack sizes of the day.
Since then, cabinet sizes have gradually grown from 24” to 32” making 30 square feet / cabinet the new space requirement norm. A typical, fully configured unified computing rack can easily require 8KW / cabinet, which would equate to over 270 watts / square foot based on a 32” cabinet, assuming all cabinets were equally loaded. Colocation providers are typically building to a minimum of 200-250 watts per square foot minimum. Many providers are advertising max densities of about to 1,000 watts / square foot, though these should be questioned thoroughly, as those are typical to maximum whip (the distribution cables) yields to a cabinet or two, and are not representative of a real sustainable average.
From an efficiency standpoint, great improvements have been made over the last decade in new data centers with regard to PUE (or power usage effectiveness). PUE is a measure of how efficiently a data center operates and is the ratio of the total amount of power used by entire data center to the power delivered to the computing equipment with the ideal of being 1.0. In 2011, I remember reading the Uptime institute had reported an average PUE of 1.8 for over 100 facilities that took part in its study. Facilities that are purpose-built and optimized have drastically improved that number. Cyrus One, is a major provider of colocation space in the U.S. and is the host of one of our OpSus Cloud Services data centers, is reporting PUEs of 1.25, and Google has reported 1.12 with a goal to get to 1.1 in 2013. If building, expanding, or looking at colocation services is in your future, research the expected PUE as it is a sure-fire way to determine the operational expenses that will be involved in running it. That said, low PUEs may require extra capital investment to produce the improved yield.
If you’re planning to expand your facility, replace it by retrofitting an existing space, build a new one from the ground up (a greenfield design), or collocate your systems with an external provider, do your homework by baselining your existing needs, planning for organic growth, including reserve capacity and headroom. We’ll discuss planning for the future in my next blog article…
Mark Middleton is the Director of Cloud Services at Park Place International. In the past, Mark worked at Christus Health as the System Director for IT Architecture. Mark has been a finalist in the Data Center Executive Excellence Awards and holds degrees in Biomedical Technology and Business Administration, as well as the highest level ITIL Expert Certification.