U P T I M E I N S T I T U T E, L L C Uptime Institute Annual Report: Data Center Density By Vince Renaud, PE and Matthew Mescall, CFM Copyright 2011 by Uptime Institute, LLC 20 West 37th Street 6th Floor New York, NY 10018 All rights reserved. The Uptime Institute s (Institute) publications are protected by international copyright law. The Institute requires written requests at each and every occasion that the Institute s intellectual property or portions of the Institute s intellectual property are reproduced or used. The Institute copyright extends to all media paper, electronic, and video content and includes use in other publications, internal company distribution, company Web sites and marketing materials, and handouts for seminars and courses. For more information, please visit www.uptimeinstitute.org/resources to download a Copyright Reprint Permission Request Form., LLC
INTRODUCTION Data center owners and operators have been sternly cautioned about the imminent and meteoric rise in the power density of their computing equipment. And, the drastic consequences on the cost and complexity of power and cooling infrastructure to accommodate racks as high as 30 kw each. In Uptime Institute field experience, pockets of highdensity equipment have been evident, but not pervasive in many data centers. Based upon this apparent divergence between the longstanding dire predictions and limited deployments, the Uptime Institute determined to confirm actual owner experience in operational, highavailability data centers. Accordingly, members of the Uptime Institute Network in North America and EMEA participated in a survey on power density in their data centers. SURVEY BASE Information was received on a total of 59 data centers: 46 in North America and 13 in Europe. Some data centers reported their information by distinct areas (rooms, pods, etc.), which provided more granular detail. The entire survey base was 1,911,000 ft 2 (177,536 m 2 ) and consumed 70.9 MW of electricity. The North American data centers totaled 1,522,000 ft 2 (141,397 m 2 ) of computer room and consumed 54.2 MW of electricity. The European data centers totaled 389,000 ft 2 (36,139 m 2 ) of computer room and consumed 16.7 MW of electricity. The data centers ranged in size from 2,400193,000 ft 2 (22317,930 m 2 ). The median size was 29,000 ft 2 (2,694 m 2 ), with the middle 50% of data centers (25 th 75 th percentile) between 13,60039,900 ft 2 (1,2643,707 m 2 ). By industry, 23 data centers were operated by Financial Services companies, 11 by IT, 5 by Healthcare and Retail, 4 Energy, 3 Colocation, and the remaining industries had 1 or 2 sites. SURVEY PARAMETERS For this survey, the area component of density is defined as the computer room floor (raised or slab) and includes the IT equipment, air handling equipment that resides in the space, and electrical distribution in that space. However, since the measurement of this space can vary from one company to another based on perceived definition or configuration differences (e.g., air handlers outside the computer room wall), Uptime Institute focused on the metric kilowatts per rack. To determine this, the survey asked respondents to clarify the makeup of the data center infrastructure. Acknowledging that many data centers contain a mix of server racks, mainframes, disk and tape storage, and network equipment, the survey provided an opportunity to breakout these types. Included in the rack quantity were populated server racks, and the equivalent measurement for mainframes and standalone disk storage. The survey excluded tape libraries and silos, and racks that were not populated or only contained network patch panels due to comparatively low power use. Additionally, some respondents answered the survey by dividing their data center into smaller sections (highdensity servers vs. tape vs. mainframes, etc.). This allows for a more granular analysis of the maximum average power use per rack. SURVEY FINDINGS The median designed power density was 68 W/ft 2 (730 W/m 2 ), with the middle 50% ranging from 5195 W/ft 2 (5521,021 W/m 2 ). The median of the current density (power currently used) was 41 W/ft 2 (437 W/m 2 ), with the middle 50% ranging from 2748 W/ft 2 (288521 W/m 2 ). A few smaller data centers were purpose built for highdensity racks and had design densities over 150 W/ft 2 (1,615 W/m 2 ). When taken as a whole, the responding data centers are using 54% of their available power, with the middle 50% using between 4573% of capacity. The following charts show the distribution of designed power density and data center size. Although the data shows a general trend that data centers designed for a higher density are smaller than lowdensity data centers, this only holds at the higher end of the design density data. That is, only the high end of the data center size and the high end of the design density are consistent with the general trend. Note that 49 of the 59 data centers are less than 50,000 ft 2 (4,645 m 2 ) and have densities below 150 W/ft 2 (1,615 W/m 2 ), with a wide range of size and density combinations. Figure 1A displays the data in International System of Units (SI) and U.S. units with axes aligned to show the conversion. Figures 1B and 1C show the data in SI and U.S. units separately. 2
Design Density vs. Data Center Size (U.S. & SI units) Data Center Size (m 2 ) 450 0 5,000 10,000 15,000 20,000 Design Density (W/ft 2 ) 400 350 300 250 200 150 4,500 4,000 3,500 3,000 2,500 2,000 1,500 Design Density (W/m 2 ) 100 1,000 50 500 0 50,000 100,000 150,000 200,000 250,000 Data Center Size (ft 2 ) Figure 1A 5,000 Design Density vs. Data Center Size (SI units) 4,500 4,000 3,500 Design Density (W/m 2 ) 3,000 2,500 2,000 1,500 1,000 500 0 2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000 18,000 20,000 Data Center Size (m 2) Figure 1B 3
450 Design Density vs. Data Center Size (U.S. units) 400 350 300 Design Density (W/ft 2 ) 250 200 150 100 50 0 50,000 100,000 150,000 200,000 250,000 Data Center Size (ft 2 ) Figure 1C The survey revealed that the highest average power use was a data center in the United States at 9.2 kw/rack. However, this was reported by a small (13,400 ft 2 ; 1,245 m 2 ), highdensity data center that appears to be built for that purpose. For all respondents, the middle 50% ranged from 1.93.2 kw/rack with a median of 2.4 kw/rack. Maximum kw per rack Max: 9.2 kw/rack Middle 50%: 1.9 to 3.2 0.0 Sites Figure 2A 4
When analyzing the data as a whole by combining separately reported pods or modules the averages declined. The maximum remained the same because that data center did not report by sections. The median declined to 2.1 kw/rack while the middle 50% range also declined to 1.72.7 kw/rack. Average kw per rack Max: 9.2 kw/rack Middle 50%: 1.7 to 2.7 Sites Figure 2B The survey facilitated an analysis of power use per rack by industry. Breaking the sites down by industry, 23 were in Financial Services, 11 in IT, 5 in Healthcare and Retail, 4 Energy, 3 Colocation, and the remaining industries had 1 or 2 sites. The previously discussed 9.2kW/rack data center was the only entry for the Transportation industry, which leads all industries. The industries with the next highest maximum average power use per rack were Healthcare at 7.8 kw/rack, Aerospace at 7.5 kw/rack, and Financial Services at 4.8 kw/rack. The two industries with the highest average power use per rack were Retail and Energy with 4.1 kw/rack. All other industries were less than kw/rack. The complete results are shown in Figure 2C. 5
kw per rack by Industry Maximum Average 9.2 9.2 7.5 7.8 kw per rack 2.6 3.6 0.9 2.9 4.6 4.8 4.1 4.1 4.1 1.8 1.4 2.4 4.5 0.5 2.9 2.4 0.0 Figure 2C When average kw/rack was compared to the size of the data center, the distribution was similar to the design density vs. data center size. Avg kw/rack vs. Data Center Size (SI units) Avg kw/rack 0 2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000 18,000 20,000 Data Center Size (m 2 ) Figure 2D 6
Avg kw/rack vs. Data Center Size (U.S. units) Avg kw/rack 0 50,000 100,000 150,000 200,000 250,000 Data Center Size (ft 2 ) Figure 2E To complement the energy use per rack, the survey gathered responses about the utilization of the racks, based on the number of rack units occupied. We found that 88% of respondents are utilizing more than half of their rack units. The middle 50% of respondents were utilizing between 5896% of their rack units. CONCLUSION One of the core objectives of this survey is to provide ground truth perspective and data to owners and operators as they plan for data center infrastructure to meet evolving IT power and cooling needs. Acknowledging that the data center industry evolves quickly, the 2011 findings are that 20kW racks are a reality for a typical data center, but not to the degree forewarned. Such high density is not pervasive enough to have a widespread impact on most of the surveyed data centers. Although respondents existing racks appear to be well utilized, there is still room to add equipment. As these rack units are filled, the power use per rack will increase. Assuming a trend that rack units are filled with higher powered servers that are well utilized, the Uptime Institute anticipates an increase in kw/rack in our next survey. Nevertheless, this survey demonstrates that the expectation for 20kW racks throughout is not manifested. In fact, at an average density of 2.1 kw per rack, this is far from being true. In an effort to provide trending data, the Institute will perform this survey annually. 7
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