10 IT Power-Saving Myths Debunked

snydeq writes "InfoWorld examines 10 power-saving assumptions IT has been operating under in its quest to rein in energy costs vs. the permanent energy crisis. Under scrutiny, most such assumptions wither. From true CPU efficiency, to the life span effect of power-down frequency on servers, to SSD power consumption, to switching to DC in the datacenter, get the facts before setting your IT energy strategy."

Comments

I dunno..

[Anrego]

I'm of the school that thinks "debunking" involves some kind of comprehensive stats or numbers or evidence weight against strongly held opinions.

This article is basically a verbose version of the "nuh uh" argument.

It's not a bad article.. but I would hardly call this "debunking".

And I totally disagree on point #2 .. maybe having _all_ your extra servers always on is bad.. but if load peaks there is no _way_ someone should be waiting while a system boots.

Re:I dunno..

[ShieldW0lf]

I've got electric heat, and I've got a pile of servers in my spare bedroom, and I never need to turn on the electric heat, because the servers heat my home.

Which looks to me like an opportunity. People pay for heat. So, put the servers where people need heat, and suddenly a liability is a resource.

Apartment buildings, office buildings and malls in cold climates should all be prime locations for a datacenter.

Re:I dunno..

[Lord Apathy]

There is also more bullshit in that statement than meets the eye. Power cycling a system can cause failure if you have cheap soldering or marginal parts. Powering up a system causes it to heat up, things expand when they heat up. If you have a solder joint that isn't done right the expanding and contracting will cause it to break eventually. I've actually seen surface mounted parts fall off a board because of shotty soldering.

Yeah, true the real problem was shotty soldering but the heating cycles helped it along.

Re:Sleep != Hibernate

[EvilRyry]

Using my handy killawatt, I tested how much power my desktop (not including accessories) draws while off, on and idle, on and under load, and in S3 suspend.

Off - 6 watts
Idle - 140W (dropped from 152W after installing a tickless kernel)
Loaded - 220W
S3 - 8 watts

Ever since I ran that test, I put my machine into suspend at every opportunity. 140W is a lot of juice in the land of $0.18/kWh.

Re:Sleep != Hibernate

[Volante3192]

My kingdom for a mod point...

I built a new system in July, Intel Core2Duo E8400, 2gb ram, ATI 3850, two hds (one's a raptor), and the box on idle pulls 81W.

My old box, an Athlon 1800+ (actual speed: 1350hz), 2gb ram, two HDs...idle was in the 130s 140s.

(Both are excluding monitor, a 20" LCD with pulls 35-40W)

So not only did I build me a faster system, it's nearly half as power hungry as my old box.

Feeling it in the 1 Watt

[Doc Ruby]

That list of myths debunked seems pretty sensible, even in details that run counter to conventional wisdom. But even though the list properly cautions several times against how most any equipment left plugged in will still drain power while doing nothing useful (infinitely bad efficiency), the article still makes an inefficienty mistake:

Sleeping continues to draw a small amount of power, between 1 and 3 watts, even though the system appears to be inactive. By comparison, Suspend draws less than 1 watt. Even over the course of a year, this difference is probably negligible.

Over the course of a year, 2 unnecessary watts is 17.532 unnecessary KWh. Sure, that's only about $1.75 at about $0.10:KWh. But that's for each device. At home, in addition to sleeping computers, there's dozens of devices with AC adapters wasting watts most of the day (and night), which is possibly hundreds of dollars wasted. In offices and datacenters, possibly thousands to hundreds of thousands of dollars a year wasted. And each KWh means loads of extra Greenhouse CO2 unnecessarily pumped into the sky, even if it's (still) cheap to so recklessly pollute.

Which is what the One Watt Initiative is designed to minimize. The US government has joined the global efficiency organization, mandating purchases of equipment that consumes no more than 1 watt in standby mode. Whatever the global impact of 3W wasted in standby can be cut by 2/3 if switching to 1W.

In the short run, that makes energy bills lower (and, by saving heat from standby devices, further lowers energy costs due to less required cooling). In the long run, we've got more fuel and intact climate left to work with - and that stuff just costs way too much to replace when it runs out.