Data Center Design & Planning - Introduction

Focusing solely on capital cost is an easy trap; the dollars required to build or expand can be staggering. Capital cost modeling is critical, but if you have not included the costs to operate and maintain (OpEx) your business-critical facilities infrastructure, you have severely shortchanged the overall process of effective business planning.

There are two critical components required to build data center OpEx cost modeling—the maintenance costs and the operating costs. The maintenance costs are the costs associated with the proper maintenance of all critical facility support infrastructure. They include but are not limited to OEM equipment maintenance contracts, data center cleaning expenses and subcontractor costs for remedial repairs and upgrades. The operating costs are the costs associated with daily operation and on-site personnel. They include but are not limited to staffing levels, personnel training & safety programs, the creation of site-specific operations documentation, capacity management, and QA/QC policies and procedures. If you have failed to calculate a 3-7 year operations and maintenance (O&M) expense budget, you cannot build a return on investment (ROI) model that supports smart business decisions

If you are planning to build or expand a business-critical data center, your best approach is to focus on three basic TCO parameters: 1) capital expense, 2) operations and maintenance expense, and 3) energy costs. Leave any component out, and you will run the risk of creating a model that does not correctly align your organization’s risk profile and business expenditure profile. If you are making a decision about whether to “buy” (use of collocation/hosting) or do an internal build, the risk of not taking this TCO approach is magnified significantly.

There are two missteps that can put your organization in the overspend death spiral. First, everyone wants a Tier 3 design, but not everyone needs one. Second, most visions of kilowatt per square foot or rack are not supported by actual business requirements. Too many times, the “must have 300 watts per square foot” approach may not be justified. Don’t overbuild; it is a waste of capital. Higher tier facilities also lead to higher O&M and energy costs. This sets the entire foundation for a proper business model and ROI off-base. Establish the right design criteria and performance characteristics first. Then build your capital expenses and operational expenses around it. Make sure to get your design criteria right and your financial model set prior to visiting the board of directors. For more information on design parameters see White Paper 142, Data Center Projects: System Planning.

Organizations often start searching for the perfect space to build before having their design criteria and performance characteristics in place. Without this vital information, it doesn’t make sense to spend time visiting or reviewing multiple sites. This typical “cart before the horse” scenario happens most frequently with users in the 1-3 megawatt range. While mega users are usually experts in this arena, and take into consideration power availability and cost, fiber, geographic issues such as earthquakes, tornados and flood plains, etc., baseline users often have business models that dictate a need to build or renovate a shell in their core region of business. The problem with selecting a site prematurely or based on narrow geography is that the site often cannot meet the design requirements. For instance, having your data center two floors below your high-rise office or even two blocks away is convenient, but business-critical data centers require a long list of site criteria that usually cannot be met in a multitenant space without significantly higher build costs or limiting space for future expansion. White Paper 81, Site Selection for Mission Critical Facilities, provides more information to help avoid this big mistake. Some organizations base their site search criteria on the amount of raised floor required to house their critical IT infrastructure. This can lead to the next big mistake

“While the physical design of a datacenter is critical, how a site is operated and maintained plays a more significant role in achieving site availability” – The Uptime Institute

The amount of space to house the data center facility infrastructure components can be significant. In the most robust of systems, the ratio of raised floor to support gear could be as high as 1 to 1. Many organizations base their space requirements on IT equipment alone. However, mechanical and electrical equipment require a significant amount of space. In addition, many organizations overlook the square footage required to house office space, equipment yards and IT equipment staging areas. Therefore, it is absolutely critical to determine your design criteria before you develop your space plan. Without it, there is no way to conceptualize the total space required to meet your overall needs.

Power Usage Effectiveness (PUE) is an effective tool to drive and measure efficiency. However, broad energy efficiency claims may lead to significant misunderstanding. In nearly all situations for new builds and expansions, there is a capital cost related to gaining lower PUE. Many times, organizations set a PUE goal with all the proper intentions but the calculation does not take into account all factors that should be considered. You need to fully understand what the ROI is on capital expenses to reach your goals. You need to ask yourself, what is the TCO relative to the target PUE?

There are many ways to illustrate and understand the breakdown of the balance between PUE, ROI and TCO. Here are three cautionary examples that represent a failure or misunderstanding:

• What was the “design criteria day” for the calculation? Was it calculated or measured on the “perfect day”? Or, was the calculation based on a yearly average?
• Was the calculation based on a fully loaded or partially loaded data center operating condition? All equipment efficiency curves change based on load profiles. PUEs change daily, if not hourly, in true operating conditions.
• Finally, there is an ongoing debate regarding the efficiencies of water-cooled chillers and air-cooled chillers. Each application has multiple options for “free cooling” or “economizer” applications to lower PUE. For this example, when making your TCO/ROI business decision, you must ask yourself the following question: What is the cost of the make-up water and water treatment maintenance requirement for the water cooled solution? Recognize that a typical 2 megawatt data center using water cooled towers will require 50 to 60,000 gallons of make-up water per day.

Use PUE to your advantage to meet your overall business goals, but be cautious. Try not to get trapped into misusing the calculation formula to justify overall capital expense and operating expense budgets.