Looking to get the most energy savings out of your data center? The newest technique, called "power-capping," may be your answer, even though at first blush it sounds like a very scary proposition.
Power-capping does exactly what it says: It limits the amount of electricity that servers can consume at any given time. This not only controls the amount of electricity used in a data center, but also increases data center density. So enterprises save in two ways: Lower utility bills, and less real estate needed for their data center.
Ted Samson at InfoWorld has an
excellent article about power capping that's well worth the read. The following section from the article, in a nutshell, is what power capping is all about:
Let's say you have a max power envelope of 1MW. For the sake of argument, let's say 400,000 watts of that megawatt goes to power, cooling, storage, and networking equipment, which leaves 600,000 watts to allocate to your servers. You decide to stick to the power allocation printed on the nameplates of your machines, which is 400W. That means that your budget allows 1,500 1U servers in your datacenter.
But what if, in reality, your servers never need more than an average 300 watts of power to maintain their required performance level? If there was a way to ensure you didn't exceed your 1MW power limit, you could pack 2,000 1U servers into the same amount of space -- with little to no need to add power and cooling infrastructure.
That's where the power capping comes in. With power capping and complementary management software, you could ensure that no server draws more than 300 watts at once. Some companies, such as Intel, have developed power capping technology that can be applied at the rack level.
The Intel technology he's talking about is called Dynamic Power Node Manager Technology. and it's designed for servers running Intel's Xeon 5500 chips. Intel also has an add-on to it called Intel Datacenter Manager, that monitors and controls power for an entire group of servers.
Baidu, the largest search company in China, used Intel's technology, says the article, to great effect. Samson writes:
In total, Intel and Baidu managed to reduce power consumption by as much as 50W at the server level, without significant impact on workload performance. At the rack level, they saw a potential for around 20 percent more capacity within the same power envelope and without performance impacts.
That's quite impressive; you can see how the energy savings, and return on investment, can add up very quickly.
Intel isn't the only company with power-capping technology. AMD, IBM, Dell, and HP all have it as well. Anyone operating a data center should start investigating the technology now, on a pilot basis. Going whole-hog at first isn't recommended; you first need to make sure you don't affect important applications. But based on the pilot, you may end up deploying it, with substantial savings as a result.
Photo CC-licensed by Flickr user j / f / photos.