Many customers continue to measure temperature of their server racks using the "back of the hand" method. Unfortunately this is exactly what it says -- they walk the aisle with the back of their hand extended and when they feel a warmer than normal area, that is an area to be looked at further. Well, yes, that's not exactly scientific, but it has worked for years. Likewise power consumption was pre-determined from manufacturer's specs which generally means it was grossly overvalued.
But as we look at better optimizing our overall energy consumption, even a degree or two difference can make a big difference in our overall energy efficiency. The "back of the hand" method cannot provide that level of accuracy, so newer methods need to be implemented. Over the last few years, IBM has introduced direct measurement within their server family for both power consumption, as well as temperature reporting. With the direct reporting of this information, immediate and accurate information can be available and leveraged.
With the availability of more accurate information in a timely matter, datacenters can reduce their "energy buffer" . Typically customers have over-cooled, and over-powered. With the ability to detect even small deltas quickly and accurately, these buffers can be reduced and therefore overall energy consumption can be reduced.
But how does one get access to this information? Tivoli's ITM for Energy Management collects this server information from its embedded Active Energy Manager component. The data can be thresholded with events generated automatically when measured values exceed expected values. Reports can be generated or the information can be visualized in an operations console.
Having accurate and detailed information is just one element of an effective overall datacenter energy strategy -- but a very important one for sure.