Valet Parking the Data Center Container: Part II

In a recent post I postulated that a midsize company’s CTO had taken the plunge and committed to boldly move forward with a containerized data center strategy. Everything seemed to be going smoothly, and the new “data-center-in-a-box” arrived in only six weeks after it was ordered by our intrepid hero. The problems began when it came time “to just plug it in," since it was ordered complete with 1,000 new servers all pre-installed and presumably ready go.

Our hypothetical CTO had indeed skipped all the tedious details (such as power and cooling requirements) and those usual endless meetings with architect and engineer construction committees normally associated with a new data center. Thus, he saved the 18 to 24 months of waiting for his new data center to be built, or so he thought. While the new containerized units did arrive from the vendor in six weeks as promised, there was no secured location to “park” his new data center, nor the supporting infrastructure to power and cool it.

Let’s look at what a containerized data center offers, and what is really involved with planning, outfitting and operating these new data center innovations.

All the major server manufacturers (HP, IBM, Dell and Sun) have announced containerized data centers this year. While each one differs in the details, they all offer systems empty or pre-loaded with the equipment of your choice. They all claim that they can provide a much more compact footprint and more energy efficiency at a much higher power density than a traditional data center. One vendor claims that its 40-foot container provides the same usable rack space as a “typical” 4,000-square-foot. data center. Moreover, some vendors state that the units can be located outside a building, exposed to the elements. However, most recommend that they reside inside in a warehouse-style building, sort of a “container hotel."

Some vendors' designs focus on primarily supporting and installing their own equipment, while others provide full-sized industry-standard 19-inch racks and offer to pre-install and configure their own IT gear, as well as other vendors' equipment. Dell has a 40-foot “Double Decker” consisting of two stacked containers that were used for Microsoft’s new data center near Chicago. The bottom container holds the IT equipment; the top contains the support infrastructure.

Part of the efficiency-improvement claims are based on the fact that the racks in containers are positioned so there is a total separation of the hot aisle and cold aisle airflow. This allows them to offer a much higher power density with lower fan power, since the air flow only needs to travel a few feet, rather than the typical 20- to 30-foot distance from the CRAC to the racks. Some containers require 208V (3-phase) power and distribute it as 208V single-phase to the rack, while others require 415V/240V (3-phase) power and distribute it the rack as 240V single-phase, to improve density and energy efficiency.

While containers do offer the potential to use less space and be more energy efficient, they still require approximately the same amount of conditioned power and cooling (chilled water only, please) that a traditional data center with a similar-sized IT load requires. So while a 40-foot (8-foot wide) container “eliminates” the need for 3,000 to 4,000 square feet of dedicated data center space (with or without a raised floor – depending on your religious beliefs), it still needs to be fed by a UPS and backup generator. If your IT equipment load is 600KW, then you will still need to have 600KW of cooling via chilled water. And by the way, for those of you who are still thinking in terms of watts/square foot, that translates to 1,875 watts per square foot (600KW/320 {40’ x 8’ = 320 sf}).  This is in contrast to a 3,200 square-foot “traditional” data center at 600KW, which calculates to 187 watts/square foot. The high-density containers can support up to 27KW per rack, which is very difficult to achieve in normal racks (non-contained) in open aisles.

There can be many arguments made, pro and con, about when and why to consider a containerized solution. However, the main advantages of these containers are that they offer the potential of rapid deployment and expansion, very high densities, higher space and energy efficiency, as well as ostensibly lower costs (when compared to the build-out costs of data center white space of equal load capacity).  There are other issues to consider, such as UL, NEC approval standards that need to be met by the manufacturers, as well as state and local building, fire and electrical codes, which were never written to deal with a container. Over time, these will be non-issues once/if there is mainstream adoption and published standards and the codes incorporate sections to deal with containers. However, for the moment, buyer beware.

Of course, there is always the question of cost. While each vendor makes its own claims, be prepared to think in terms of least $1 million or more for a 40-foot unit (before the IT equipment costs). This excludes the required supporting infrastructure: UPS(es), backup generator(s) and chiller plant. Ostensibly, the vendors all claim that the overall cost is still lower than a comparably-rated (in power, not size) traditional data center.

Now as to the last line in the first part of this article, “the cold aisle operates at 90°F." This was quoted directly from Steve Cumings in the HP “POD” video.

While a 90°F “cold” aisle is what most data center customers would consider “server-cide” and is well beyond the ASHRAE 9.9 expanded temperature envelope (which tops out at 80°F), HP seems willing to back it up with its own IT equipment. Clearly, it has thrown down the gauntlet to other manufacturers to “top this” as a way to improve the energy efficiency of their “POD” containerized data center. It would appear that it is overstressing the IT equipment, but according to HP and to most other vendors' published specifications, 95°F is the limit (fine for servers perhaps, but not so advisable for tape drives). Of course, I think that most users will opt to run their cold aisles at 80°F or less, if only to be able to sleep at night. Clearly, it will take some getting used to these new computing environments, both from a facilities and IT perspective.

It is still uncertain if these containerized data centers will be a niche market, or only are going to be used by the largest players such Google and Microsoft. Perhaps they will become the new data center paradigm as we strive for more efficiency and flexibility via cloud computing in a “module." In essence, they represent the next level of a computing “building block," a mindset much like blade servers have become, the almost a de-facto standard for many server consolidation/virtualization projects. Just call your favorite IT vendor and ask for its supersized “40-foot blade server” with 1,000 blades.

And so in keeping with our blog’s name, if the HP POD container’s cold aisle runs at 90°F, then we anticipate that the rear of the racks will run 20 to 25° hotter, at the proverbial 110 degrees (or more) “in the shade."  Accordingly, HP wins our first award for possibly having the “hottest” hot aisle, but perhaps the highest efficiency as a result.