Energy efficiency and sustainability for IT infrastructures is clearly a major discussion today. There are of course quite a few environmental reasons to think about this but besides this, lowering the use of energy also improves the TCO and reduces the cost of IT infrastructures.

SAP is itself fully committed to improve the energy efficiency of SAP infrastructures and has started several initiatives during 2009. There was for example the announcement of the Green IT community at SAP Virtualization week 2009 and toward the end of 2009; the first SAP Power Benchmark was released.

One example how improved energy efficiency can be achieved with SAP infrastructures is the new Windows Server 2008 R2 operating system which has a feature called Core Parking. This feature in turn is using the underlying technology in modern multi-core CPU’s from Intel or AMD. The whole idea is basically to send cores to sleep whenever the workload of a server does not require all the available performance of this server.

Let’s for example assume a server for Hyper-V where only a few virtual machines are running. The scheduler in the parent OS would now arrange the threads for this workload to run on the fewest possible Processors. The idle processors than would be ‘parked’ which basically mean changes the ACPI power state of this cores so that they consume the least amount of energy. Vice versa, if the workload in this server grows, the OS would instantly wake-up those cores and make it available for processing.   The good point here is, it happens in the kernel and is completely transparent to the applications. Measurements on the benefit of Core Parking have shown that it yields up to 15 % of energy saving – of course depending on the workload.

As Windows Server 2008 R2 is now supported by SAP for the usage of a Hyper-V server, Core Parking would be another good reason to install the latest version of Windows whenever SAP on Hyper-V comes into play.

Have fun using Windows Server 2008 R2

-          Josef