IT professionals often over-build their cooling and power systems in data centers because they misunderstand or miscalculate necessary thermal requirements, experts say. Such misjudgments can result in the unnecessary purchase and installation of hundreds of thousands of dollars of computer room air conditioning units and power supplies, and far-too-cool data centers.
ORLANDO – IT professionals often over-build their cooling and power systems in data centers because they misunderstand or miscalculate necessary thermal requirements, experts say.
Such misjudgments can result in the unnecessary purchase and installation of hundreds of thousands of dollars of computer room air conditioning (CRAC) units and power supplies, and far-too-cool data centers.
“Data center managers are not understanding the power and heating requirements of servers and storage,” says Brian Garrett, an analyst for Enterprise Strategy Group. “There is a huge problem over-provisioning the data center.”
At Storage Networking World last week in Orlando, Don Beaty, president of DLB Associates, an engineering and consulting firm, told attendees that discrepancies exist between the power requirements given on the nameplate on the back of the system and on the detailed configuration specifications that vendors such as EMC, HP, IBM and Sun prepare for the equipment when they manufacture and test.
IT often will err on the side of caution and use the nameplate information to calculate the amount of cooling and power they need when they add servers or storage.
The discrepancy between the nameplate information and the detailed specification can lead to an overestimation of power requirements of 25% or more, Beaty said.
“Equipment nameplates are not a good source for characterizing the power and cooling load,” he said. “Nameplates are regulatory-required labeling focused on safety” alone.
The nameplate information is based on a future capability for a fully configured and loaded system, while the thermal report reflects both the minimum and maximum power loads required for the current system.
Nameplates, while listing absolutely safe requirements for operation in the harshest conditions, should not be used to calculate thermal conditions, Beaty said.
Instead he pointed IT to thermal reports that companies such as EMC and Cisco complete on their products.
These reports, which vendors developed in cooperation with the American Society of Heating Refrigerating and Air-Conditioning Engineers (ASHRAE), are now included with any new gear users buy.
For instance, the IBM Server Model 520 Thermal Report shows a heat release of 420 watts for the minimum configuration and 600 watts for the maximum configuration while the nameplate indicates 1,000 watts, a 40% to 60% increase.
If a data center manager was to have an additional CRAC unit installed to supplement this 40% to 60% power increase, it would cost approximately $100,000.
But Beaty added that it is not always easy for IT to get a copy of the Thermal Report from their vendors.
“The manufacturers are just starting to modify their documentation to use the Thermal Report, so it currently is not easy,” he said. “Publicity will help to expedite this.”
Beaty also recommended IT managers purchase a book ASHRAE published this year called Thermal Guidelines for Data Processing Environments, which will help them better understand power and cooling issues in their data centers.
