Data Center Temperature Monitoring: Raised Temperatures, Riskier Management
In 2008, American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) published new environmental guidelines for datacom equipment. They increased the high-end temperature from 77°F to 80.6°F.
The guideline chart below shows the changes in more details:
According to the 2008 guideline, the recommended operating environments could not ensure optimum energy efficiency. There are varying degrees of energy efficiency within the recommended zone, depending on the outdoor temperature and the cooling system design. Thus, the guideline suggests, “it is incumbent upon each data center operator to review and determine, with appropriate engineering expertise, the ideal point for their system”.
Patrick Thibodeau, reporter at computerworld.com, conducted an interview with Roger Schmidt, the IBM chief engineer for data center energy efficiency, about how the new temperature parameters will influence energy savings and data center cooling. When asked “how much heat can servers handle before they run into trouble”, Schmidt replied:
“The previous guidelines for inlet conditions into server and storage racks was recommended at 68 degrees Fahrenheit to 77 Fahrenheit. This is where the IT industry feels that if you run at those conditions you will have reliable equipment for long periods of time. There is an allowable limit that is much bigger, from 59 degrees Fahrenheit to 89 degrees. That means that IT equipment will operate in that range, but if you run at the extremes of that range for long periods of time you may have some fails. We changed the recommended level -- the allowable levels remained the same -- to 64F to 81F. That means at the inlet of your server rack you can go to 81 degrees -- that's pretty warm. [The standard also sets recommendation on humidity levels as well.]”
He also revealed that 81°F is a point where the power increase is minimal, because “raising it higher than that [the recommended limit] may end up diminishing returns for saving power at the whole data center level.” In fact, according to GSA, it can save about 4% to 5% in energy costs for each degree of increase in the server inlet temperature.
Too much humidity will result in condensation, which leads to electrical shorts. According to GSA, “based on extensive reliability testing of Printed Circuit Board (PCB) laminate materials, it has been shown that conductive anodic filament (CAF) growth is strongly related to relative humidity. As humidity increases, time to failure rapidly decreases. Extended periods of relative humidity exceeding 60% can result in failures, especially given the reduced conductor to conductor spacing common in many designs today.” The upper moisture region is also important in protecting the disk and tape from corrosion. Excessive humidity forms monolayers of water on device surfaces, providing electrolyte for corrosion. On the other hand, too little humidity will leave the room electro-statistically charged.
After the new standards were published, it would take time for the data centers to update their operating rooms. According to Schmidt, IBM started using the new guidelines internally since 2008, and some other data center probably would step it up two degrees at a time. To run near the new ASHRAE temperature limits means a higher risk environment for staff to manage and requires more operational expertise. According to 2013 Uptime Institute survey data, nearly half of all data centers reported that their systems ran at 71°F to 75°F. 37% of data center reported temperature from 65°F to 70°F, the next largest temperature segment. The trend to warmer data centers is better revealed by the fact that there were 7% data centers operating at 75°F or above, compared with 3% in the year before.
ASHRAE, “2008 ASHRAE Environmental Guidelines for Datacom Equipment”
Patrick Thibodeau, “It's getting warmer in some data centers”, 07/15/2013.
Patrick Thibodeau , “Q&A: The man who helped raise server operating temperatures”, 07/06/2009.
Ivory Wu, Sharp Semantic Scribe
Traveling from Beijing to Massachusetts, Ivory recently graduated with a BA from Wellesley College in Sociology and Economics. Scholastic Ivory has also studied at NYU Stern School of Business as well as MIT. She joins Temperature@lert as the Sharp Semantic Scribe, where she creates weekly blog posts and assists with marketing team projects. When Ivory is not working on her posts and her studies, she enjoys cooking and eating sweets, traveling and couch surfing (12 countries and counting), and fencing (She was the Women's Foil Champion in Beijing at 15!). For this active blogger, Ivory's favorite temperature is 72°F because it's the perfect temperature for outdoor jogging.