When I first started designing containerized datacenters, I looked at them as ways to tidy up many of the problems bedeviling the IT department, such as acceptance testing, installation disruption, cabling, and overall performance. As things evolved, we found ways to reduce inefficiencies in power utilization.In turn, this led to x64 server designs that are more efficient still, and the efforts spent in improving unit cooling led to the realization that the traditional concept of providing a chilled air environment was fading into the history books.
A lot of factors make this increase in power usage effectiveness (PUE) possible. The advent of multi-core x64 CPUs keeps the power profile in a typical 1U server constant, while boosting power tremendously. Lower power memory matches the CPU, so that current servers have much better GFLOPS/watt. At the same time, power supplies are capable of much better efficiencies today, reducing the heat load in the server box.
The largest breakthrough came from the realization that cooling had to be decoupled from the server engine in a container. We tried water cooling (it leaks!), roof refrigeration and sidewall refrigeration. In the process, it became obvious that we could drop the chilling if we used bigger fans on the servers, and with racks full of the same structure, we could use 5-inch or bigger fans for cooling. (A techy aside — the bigger the fan, the better the airflow, and it’s roughly a square law, so a 5-inch fan versus a ¾-inch fan is no contest!)