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Temperatures in data centers have been inching up over the last few years as industry standards have relaxed around operating temperatures, once strictly limited. Less than a decade again the norm was for data centers to operate in a narrow band, a target of 65°F and 50% relative humidity. Contrast that to today where you can find many hyper-scale data centers operating at temperatures in excess of 90°F with very broad 20 to 80% humidity limits. So what has changed?

 

Here are three factors driving increases in data center temperatures.

 

Equipment evolution. One major change has been the data center equipment itself. Not only have the various equipment manufacturers broadened the acceptable operating range, there has also been a reduction in the kinds of equipment like printers and tape drives which require stricter environmental specifications.

 

Free cooling. Energy conservation has been another driver for warmer operating standards as available free cooling hours (on an annual basis) increase for each degree of increase in the data center. (Free cooling is an approach that uses naturally cool air or water instead of mechanical refrigeration to lower the air temperature in a data center.) In fact, in some cases, data centers are being strategically located in climates where 100% free cooling is available using solely outside ambient air or in combination with low energy use evaporative cooling systems, thereby eliminating any refrigeration device.

 

Changes in perception. In the past there was the perception that the cooler you can keep the data center, the more time you have before systems crash from overheating, especially in the event of a cooling failure. The fact is data center temperatures quickly rise when cooling systems fail, often much more quickly that cooling systems can be repaired. As a result, allowing data centers to run warmer to take advantage of free cooling efficiencies has become more widely adopted.

So what are we doing at NetApp IT?

 

NetApp was an early adopter of elevated data center operating temperatures. We have been using elevated temperatures, i.e. 75°F, in our data centers since 2009 when we opened our Global Dynamic Lab 1 (GDL-1) in Research Triangle Park, North Carolina. This approach allows us to maximize the use of ambient air free cooling resulting in a very low overall energy use for cooling the data center. In fact, NetApp’s GDL-1 was the first ever Energy Star rated data center and currently has the highest possible score (100) in the Energy Star database.

 

Curious about why we don’t keep our data centers even warmer and further reduce energy use similar to the hyper-scale cloud providers who operated in the 1990s? The answer is simple. Given the nature of how our data centers operate, we have people who work in our data centers whereas others operate on a “lights-out” basis. Even though our data centers are 75°F on the “cold” side of the supply in our cold room, the air exits the racked equipment at about 90°F in the hot aisles which is where the majority of NetApp employees service the equipment. So even though the equipment could handle warmer temperatures, our upper limits are based on human comfort for the NetApp employees who work in our data centers.

 

To find out more about NetApp’s data centers, check out our past blog posts, What is a GDL and Why Do We Need Two? and The Hillsboro Data Center: The Foundation of the NetApp IT Hybrid Cloud Transformation.

 

The NetApp-on-NetApp blog series features advice from subject matter experts from NetApp IT who share their real-world experiences using NetApp’s industry-leading storage solutions to support business goals. Want to learn more about the program? Visit www.NetAppIT.com.

Mark Skiff