You May Be Over Paying for Data Center Power

It’s All About the Density

One of my earliest clients (circa 2000) wanted to completely fill a standard colocation cabinet with as many servers as it could physically hold. While logical, this was a big issue for us as our data center at that time could only cool a single cabinet up to 2 kilowatts (KW). This meant that while physically it could fit 42 servers into a single cabinet, we didn’t have the cooling capacity to keep up with such heat in such a small space. Packing the cabinet this full, would not only cause the equipment in the cabinet to overheat, our data center would be too hot to host any other equipment even though we had plenty of physical space left.

So our ability to cool our cabinets looked like this:

20 amps @ 120v = ~ 2KW
What our client wanted to do
84 amps @ 120v = ~ 10KW

Welcome to The Low Density Era

For those that had small equipment which drew a lot of power, I sometimes had a hard time explaining that they’d need to buy an additional cabinet and split the servers between the 2 cabinets which left huge gaps intended to help with cooling. To make matters more interesting, blade servers were introduced which allowed much higher computing in a smaller footprint. As IT departments upgraded their equipment from traditional servers to Blade servers, I was called upon to “rescue” IT departments from these low density colocation facilities into facilities that would cool well past 2–4KW per cabinet.

The Work Arounds

At this point in history it was normal that a data center could cool 10KW but innovators and more modern facilities saw the trend for even higher computing and began to build 10KW and 15KW cabinet cooling capabilities. Older facilities needed complete retrofitting to get close to this or added drastic measures like in rack cooling, expansions in cooling equipment coupled with baffles, more porous floor files and a host of other stop gaps.


Enter 2020. In our 515 Engine database, we have facilities that can cool above 60KW of power per cabinet in taller cabinets designed to pack in hardware. With this advanced cooling capability one could not expect that the per cabinet pricing would be the same as the 2–4KW cabinets of old. While not everyone can go up to 60KW of cooling, it seems that a norm has settled into the 10–20KW cabinet range.

In a recent project, our client was running closer to 6–8KW. They had a very specific technology stack that didn’t need blade servers. As I worked with reps of various colocation facilities, we had to purposely locate and quote data centers that were slightly older. While my client was ok paying for the 8KW of power they needed, I knew that putting them into a facility that was constructed to accommodate far greater densities meant they’d pay a premium. We ended finding a facility built to cool high density but not ultra high density power usage. The price per square foot in this space was substantially less than others.

With this strategy, the only risk for my client is if they change their technology stack to ultra high density they maybe forced to move. Since there are no plans to increase their density for quite some time, we thought this would be fine.


Having a perfect understanding of your power consumption by the rack is critical. It’s literally the first step we take when we engage with any of our clients. Depending on your hardware vendor, there are great power calculating tools out there.

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