Design Process

The design stages for the data center usually take the skills of architects , accountants , structural, mechanical, electrical, HVAC, system, and network engineers, project managers, and procurement personnel. Add also the probability of sales personnel, insurance carriers , and risk management analysts. Overseeing the project is a data center design engineer whose task is to accommodate the requirements of the system and network engineers , and to work with the other members of the team to ensure that the data center requirements (based on the project scope) are met.

As in any other design process, this is an iterative and recursive process. You have an initial set of criteria and you use this set of criteria to determine requirements. You define rack location units (RLUs, described in Chapter 4, "Determining Data Center Capacities ") to ensure that the requirements match or exceed the criteria. At certain points other criteria will emerge. These, in turn, change the requirements. And additional or different RLUs will be needed to verify these requirements meet or exceed this new criteria. This is how the process is iterative. Other times, requirements change, and this changes the criteria which in turn changes the requirements. This is how the process is recursive. After several passes through this iterative recursion, a stable set of criteria and requirements will emerge. The changes become smaller in scope, and the process continues as before, albeit with a finer level of granularity.

Just when you think you have a handle on the whole design, somebody tries to get code approval for something, won't get it, and you end up very close to square one. You then have a great screaming match with a white board marker because you're convinced it picked that exact moment to dry up on you. You're certain that its reason for doing this was just to annoy you (the fact that you left the cap off for three days is irrelevant). Finally, you decide to see how far you can throw it across the parking lot.

Then, you and a few friends head off to the pub for a few pints. You become more rational and realize, "Oh, it's not that bad We can just add another network POD in this other row and that will fix the problem, and I can figure that out tomorrow morning in fifteen minutes." Things get back to only mild insanity for a few days until a similar event triggers similar behavior. Over time, the problems get smaller and eventually the design meets the criteria.

While the description of events above might seem a little over the top (you usually end up throwing your dead white board marker across your office rather than the parking lot), it is not that far from the truth. If you are embarking on designing and building a data center, remember this above all else: Find ways to have fun, enjoy the process, and learn to see the humor in some of the bizarre situations you'll find yourself in. If you don't, you might as well get a long- term lease on a padded cell and start your fittings for a jacket with sleeves that tie behind the neck.

Design Drawings

It should be kept in mind that the design of a data center should be structured but fluid, not only during the design process, but after construction. Computer environments constantly evolve to accommodate company needs, changes in technology, and the business landscape. Professional, detailed plans are necessary in the design stages, but it is important to keep updated working drawings of the data center and all support systems.

Computer Aided Design (CAD) software is typically used. It is more efficient than drawing by hand, and creates plans that are clearly readable, easily reproduced, and easily modified. These blueprints allow for the continued updating of architectural, electrical, mechanical, and computer systems. The drawings can be used in site evaluations and future planning.

Blueprints are particularly important when the project involves outside contractors. Some of the primary contractors are:

• Architectural firms. They might supply actual drawings of the building, showing a wall here, door there, lobby over there, where carpet will be installed, where concrete will be used. This represents the physical building.

• Interior designers. They create the "look" of the place, sometimes matching company specifications for consistency of styles, from trim to carpet.

• Structural engineers. They make sure the building will use materials and construction techniques that will keep the roof from collapsing under the weight of all those cooling towers .

• Electrical design firms and engineers. They deal with lighting plans, electrical distribution, wireways under the floor, breaker subpanels, power transformers , wiring for the fire detection system, and smoke alarms.

• HVAC design firms. They determine HVAC unit placement and whether they should be 20-ton or 30-ton, determine proper installation of piping that brings chilled fluids to units, and where cooling towers, compressors, and heat exchangers will be located.

Some of these tasks , such as electrical and HVAC, might be handled by the same firm. It could depend on who is available in the area. It is a good idea to employ a project management firm to coordinate all of these different contractors.

Figure 3-1. Large Scale Design Drawings from the General Contractor or the Project Management Company

Thanks to the Internet, you can access the drawings electronically (Adobe PDF format works well for this). This can reduce the time of the design/review/change process considerably. The CAD drawings are usually held by the building contractor who helps coordinate all the other subcontractors . PDFs are good, but, a few times in the cycle, you will need actual blueprints which are larger in scale than most computer monitors . These allow you to see very fine details that might be lost in a PDF file. Also, they provide a place to make notes directly on the drawings for later use.

During the design process, you should also have several dozen pads of Post-It Notes for temporary comments on the blueprints and to bring certain details to the attention of others. You should also have a large white board with lots of dry erase markers in a variety of colors. (Remember to put the caps back on the markers when not in use.)

Designing for Data Center Capacities

A major problem in designing a data center is determining how to support equipment of known quantity and capacities, or determining the quantities of equipment of unknown capacities for a data center of known capacities. In other words, how do you make the equipment fit the room, or how do you make the room fit the equipment? There are many factors to consider and often these factors are limitations. Looking at the problem from the point of view of capacities is helpful, but you can also think of these as limitations, which is usually the case. The room might only be so big and the power company might only be able to give you so much electricity. Some of the major limitations are:

• Budget

• District

• Insurance and building code

• Power

• Cooling

• Connectivity

• Site

• Space

• Weight

A delicate balancing act must occur between many of the members of the design and build team to determine the capacities and limitation,, and to work with them. With this knowledge, factors can be juggled to decide how to implement what is available to meet the project scope. If the limitations are too great, the project scope must change.

This book offers a useful (some might say essential) tool for designing based on data center capacities called RLU. This is discussed in greater detail in Chapter 4, "Determining Data Center Capacities."