What is an Efficient Data Centre and how do I measure it ?

As this is the first time posting here, here is a quick intro, I started out as a hardware designer for a UK computer company - back in the days when the PC was still a grey tin box with a 4.77MHz 8088 inside. I have been with Intel now for more years than I care to think about, with much of this time working with the OEMs and end-customers focused in the server market across EMEA.

As I trawl thru the press and listen to the industry analysts one topic that everyone is discussing is 'data centre efficiency' ( even elsewhere on this forum , ) but what's not real clear is what defines an efficient data centre - is it the efficiency of the servers, the cooling subsystems, the workload that can be handled in a given time or the operational processes that are in place to run the data centre ? And once you have decided what is considered 'efficient' how do you measure or quantify this efficiency.

Currently there are several approaches being considered by the industry to measure data centre efficiency, and I thought it would be worth spending some time looking at three elements that can affect DC efficiency - power, utilisation and process. Given the complexity of the topic I plan to take this in bite sized chunks ( rather than write a mass of text and lose the thread ). So, in this blog I will cover power and will come back to the topic in a subsequent posting to look to the other elements. If you think there are elements to DC efficiency that I am missing please feel free to chip in and provide your insights.

Power Efficiency - Measuring the ratio between the facilities load - cooling, power conversion etc vs. the IT load - compute/storage/infrastructure. Typically this approach focus's on the ratio of electrical power consumption of the various elements within the data centre. With the current focus on the 'environmental & green' aspects of data centres this seems to be the area where most of the attention on Data centre efficiency is focused.

If you look at the average Data Centre today its not just the compute infrastructure that consumes the Watts, power gets consumed by the cooling systems and air conditioners, voltage conversion & battery storage, lighting etc. All this contributes to the 'facilities load' - for many IT managers this does not hit their IT budget and they may not even see the power bill from the utility company so have no idea how much power is consumed by these key elements of their data centre. Current estimates indicate that upwards of 50% of the power that comes into the average data centre gets 'lost ' in the facilities load, more details here & here

There are several groups looking to quantify energy efficiency The Green Grid is working on metric called PUE ( Power Usage Effectiveness ) to measure the ratio of power consumed by the facilities load vs. the power available to the IT equipment in the data center - details in their white papers here. Also the Uptime Institute are doing something similar and various government institutions are getting interested as well and there's an extensive US govt white paper ( if you have a few hours spare to ingest its 150 pages) . In addition the European Union is working on a Data Centre Code of Conduct

The server OEMs are also working on a benchmark for measuring perf/watt ( ), these are great for measuring how good a server is on a test workload and how many transactions it can deliver for a given power input. With the increased focus on energy efficient performance this metric will become more and more important to the specifiers and purchasers of servers. With Intel's latest generation 45nm quad core Xeon processors we continue to drive up the performance a processor can achieve for a given Watt input, the challenge for the rest of the industry now is to lower the overall power consumption of the other elements within the server and to increase the throughput of the storage and I/O subsystems to complement the increase processor performance. But at the end of the day does a good perf/watt for a server indicate that a data centre is efficient ?

What's missing from this approach is that there is often no consideration made as to the utilisation of the servers within the data centre consequently it might be possible to achieve 'good' power efficiency numbers but have low server utilisation and hence not extracting the most workload out of the data centre. Here in EMEA we have initiated a Data Centre Efficiency Award to try and start to get a handle how best to identify DCs that are running best practices and delivering of power and utilisation efficiency.

I guess the question at the end of the day is do you consider that your Data Centre is efficient and how are you quantifying this efficiency ?