Should You Power Down Your Servers to Save Electricity?

Should You Power Down Your Servers to Save Electricity?

For years, there's been a great debate among consumers whether turning off their PCs at night is a good way to save electricity, or whether it reduces the lives of their computers. Now, with power-savings one of the core missions of Green IT, professionals are debating whether they should power down servers at night as well.

An InfoWorld article claims that powering down servers won't reduce the lives of servers, and in fact may help you uncover latent hardware problems, because power-on diagnostics will be performed daily. And clearly, powering down servers at night can save significant amounts of electricity.

Not everyone though, agrees that it's a good idea to power down servers. In a follow-up article, InfoWorld interviewed quite a few experts, with some warning against turning off servers at night.

Brad McCredie, an IBM fellow for the Systems and Technology Group, for example, told InfoWorld that doing it stresses server components, and can cause failures. Mark Monroe, director of sustainable computing at Sun, agreed, telling InforWorld:
Most server vendors today say they'll support a certain number of cycles of powering things on and off. I believe most of the server vendors would say [the number] is in the hundreds as opposed to the thousands.
They don't have the last word, however, because quite a few experts and companies disagree. Cisco, for example, has begun shutting servers down in batches, and VMware offers a feature in VMware Infrastructure 3.5 that powers servers on and off to reduce power.

What does this mean for you, if the experts don't agree? You can try a middle ground, by using software that powers down individual components in a server, without shutting off the entire server. IBM's Active Energy Manager, for example, which is an add-in to IBM Systems Director, can do that. (For details, click here.) Sun has a similar piece of software.

You can also try your own pilot program, powering off a small number of non-mission-critical servers at night, calculating how much power you save, and seeing whether server lives are shortened. It could end up savings a substantial amount of electricity.
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