Steve Gunderson, Contributor
Published: 01 Feb 2013
When pondering a redesign, keep data center power requirements in mind as you look at new data center designs.
Even if New Year’s is a distant memory, the first quarter is still an apropos time for resolutions and goal-setting. A key theme always seems to be saving money.
Anyone with data center responsibilities trying to save money should look at in-cabinet power design.
I walk through hundreds of data centers during the course of a year, and it’s staggering to see how many cabinets have overprovisioned or underprovisioned power. Stated simply: Excess power wastes money, and insufficient power places an organization at significant risk. Neither situation is optimal, and both are easily fixable.
Spending too much on data center power
One common mistake is calculating power needs by adding up a manufacturer’s nameplate specifications. Equipment manufacturers’ power specifications are set at maximum rated output, based on the heaviest possible usage or load. But real-world experience and best practices show a much more likely usage of about 30% of that nameplate.
If you’re paying your colocation provider based on circuit capacity, designing your in-cabinet power to carry the maximum load on every device typically results in an oversubscription of power of two times or more, which can equal thousands of dollars a month in electricity costs for capacity you’re not using.
For instance, one client rented colocation space for 12 cabinets of gear, but only 10 were used in production. When the company designed its in-cabinet power, it ordered 30 amp circuit pairs for every cabinet, not realizing that the colocation provider would charge them for the circuits installed in empty cabinets. By leaving the cabinets offline until they were needed, the client was able to save nearly $2,400 a month.
Underpowered servers spell increased costs
Conversely, I also run into far too many internal data centers with underprovisioned cabinets, placing the operating environment at great risk. Imagine a typical server cabinet with two 30-amp circuits (with “A” and “B” circuits for redundancy). Best practice dictates that the maximum continuous draw should be no greater than 80% (or 24 amps). Yet more often than not, we see cabinets drawing 40 amps on those two 30-amp circuits. One hardware blip or power surge would put that cabinet at great risk for an outage.
Easy-to-use tools are available to assist in correctly sizing power requirements as well as with the design of the overall data center power allocation. A data center consultant can assess your data center design and make recommendations for improvements.
Whatever you do, don’t let another year pass by without addressing in-cabinet power consumption and supply. The days of evenly distributing power throughout your entire data center at X watts per square foot are over. Data centers today should include optimized power distribution layouts where the supply to each cabinet accurately reflects the equipment inside.
About the Author:
Steve Gunderson is a principal at Transitional Data Services.