Windows Server 2008 R2 contains a number of efficiency improvements designed to lower the costs of operating your Windows servers. These days, with so much emphasis being placed on environmental concerns, energy costs, and the general expenses of doing business, one area that is garnering a lot of attention is server power consumption.
While data centers grow and servers become both elastic and cheap, power usage can shoot through the roof, causing corporate budgets to take a serious hit.
But even if money isn't the primary concern, data centers themselves might be constrained by their size. Some utility companies -- especially in remote areas -- may have service limits which restrict the amount of power that can be drawn by any one facility. This can not only limit the number of computers located in the facility, but also how many machines can have active or awake at any given moment. By saving power, companies can have more machines in the same location without increasing power consumption.
So how will Windows Server 2008 R2 lower power consumption in comparison to identically-configured servers running the gold versions of Windows Server 2003 or 2008? There are three primary ways:
Adjustable processor speed: New to Windows Server 2008 R2 is the ability to adjust the ACPI P-states of processors. These are the states within the ACPI power architecture that govern speed, performance, and power use depending on workloads.
With most modern server-class processors, the operating system can change the P-states of individual processors on multiprocessor systems, and thus very granularly control the power needed to run the system.
Lower processor power use on systems with multicore chips: By using a feature called Core Parking, Windows Server 2008 R2 lessens the power used by multicore processors. This feature moves processor workloads and consolidates them onto the fewest possible number of cores. It then suspends the unused cores. (Remember when you used to park the heads of your hard drive in DOS?)
Lower power of storage area network (SAN) system components: Windows Server 2008 R2 makes it easy to bring centralized storage into your network, reducing the need for multiple drives on each server spinning up and staying awake to service requests.
SANs are more efficient in power usage because they generally consist of higher capacity drives that require less overhead, improving their ratio of capacity-to-power use. In addition, since any server can use the available space in a SAN, you have less wasted disk space. Windows Server 2008 R2 includes many features designed to interface easily with SANs, including cluster services.
Some of these power consumption adjustment features have also been backported to Windows Server 2008 SP2, meaning many existing Windows Server 2008 customers can take advantage of them. The comparisons in power usage, however, are most dramatic when looking at Windows Server 2003 versus Windows Server 2008 R2.
ABOUT THE AUTHOR
Jonathan Hassell is an author, consultant and speaker residing in Charlotte, N.C. Jonathan's books include RADIUS, Learning Windows Server 2003, Hardening Windows and most recently Windows Vista: Beyond the Manual.
This was first published in July 2009