10 IT Power-Saving Myths Debunked 359
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."
Questionable grasp on the problem space. (Score:5, Insightful)
Myth No. 3: The power rating (in watts) of a CPU is a simple measurement of the system's efficiency.
Fact: Efficiency is measured in percentage of power converted, which can range from 50 to 90 percent or more. The AC power not converted to DC is lost as heat...Unfortunately, it's often difficult to tell the efficiency of a power supply, and many manufacturers don't publish the number.
I'm not sold on taking advice who doesn't understand the difference between the wattage rating of a CPU and the wattage rating of the power supply. They're completely different components.
Debunk this (Score:5, Insightful)
Did I miss something? (Score:5, Insightful)
Did the definitions of 'fact' and 'debunk' change recently? Every 'myth' listed has 'fact' under it proving it is true. According to my good friend Mr. Webster this is called 'confirmation.'
Re:Questionable grasp on the problem space. (Score:5, Insightful)
Myth No. 9: Going to DC power will inevitably save energy.
Fact: Going to DC power entails removing the power supplies from a rack of servers or all the servers in a datacenter and consolidating the AC-DC power supply into a single unit for all the systems. Doing this may not actually be more efficient since you lose a lot of power over the even relatively small distances between the consolidated unit and the machines. New servers have 95 percent efficient power supplies, so any power savings you might have gotten by going DC is lost in the transmission process. Your savings will really depend on the relative efficiency of the power supplies in the servers you're buying as well as the one in the consolidated unit.
This is completely wrong. The author missed out on two of the three power conversions that take place in a data center. Data center UPS units take the AC current convert to DC then back again just so the server can convert it back to DC. Even if you have 95% efficiency at each stage the conversion losses will add up.
People wouldn't be going DC if it didn't result in measurable power savings.
Re:Single page (Score:1, Insightful)
Re:For mere mortals there is speed (Score:2, Insightful)
What are they running? Corporate Crippleware: Safe Boot. Virus Checkers. Keyboard Loggers (Hi, guys!). After a few "Regime Changes" it all adds up...
Re:For mere mortals there is speed (Score:3, Insightful)
lots of companies have lazy desktop admins who write one giant script to run that checks every resource available in the system for every user even though most of those users will not use most of the resources it is checking for. Smart companies have created multiple scripts and figured out smart ways to quickly identify what scripts the logging in user needs to run, thus reducing boot up significantly.
I'd Get Fired If I Followed These (Score:2, Insightful)
Myth #2 suggests making your customers wait. That might work in super-mega-corporate land where your customers are literally married to you and queues in Tech Support are "profitable."
I would *deserve* to be fired if I made a customer wait. Of course, that sense of urgency doesn't work in super-mega-corporate entities either.
The myth about going to DC to be more efficient is painful too. If a manager in a workplace would entertain a crackpot ideas like that, I'd leave.
Re:I dunno.. (Score:5, Insightful)
I stopped reading at #1: "Fact: The same electrical components that are used in IT equipment are used in complex devices that are routinely subjected to power cycles and temperature extremes, such as factory-floor automation, medical devices, and your car."
Well, yes, except for the fact that the it's a total lie. Cars, factory automation, and medical devises most certainly do NOT use "the same" components. While they may do the same things, and even be functionally equivalent, they are rated to much higher temperature and stress levels than consumer or even server grade components. Just ask the folks who have been trying to install "in-car" PC's with consumer grade components.
Re:I dunno.. (Score:3, Insightful)
(also, why the hell was my last post modded down as redundant?)
Probably because a similar point was already made in TFA:
You can also select systems that cold-boot rapidly. Model to model and brand to brand, servers exhibit wide variances in power-up delay. This metric isn't usually measured, but it becomes relevant when you control power consumption by switching off system power. It needn't take long. Servers or blades that boot from a snapshot, a copy of RAM loaded from disk or a SAN can go from power-down mode to work-ready in less than a minute. The most efficient members of a reserve/disaster farm can quiesce in a suspend-to-RAM state rather than be powered down fully so that wake-up does not require BIOS self-test or device querying and cataloging, two major sources of boot delay.
I remember why I don't read Infoworld (Score:4, Insightful)
That's a really bad article. Wow, worse then anything I remember them writing before.
Re:I dunno.. (Score:5, Insightful)
However, silicon is silicon, capacitors are still made from the same things
Thank you for playing the game, but you have lost [badcaps.net]. Rather then using more expensive Nippon electronics, the Chinese parts you used had a few part per million more impurities. This lead to early thermal failure of your mainboard.
If you would like to play the game again, please acquire more venture capital and buy quality next time. You may still lose the game to your manufacture buying counterfeit parts, using the wrong specification solder, or unforeseen interactions from running at many gigahertz at high temperature.
This show has been hosted by an automation robot that costs 75 times what your laptop does and still has occasional electronics failures. :)
Re:Questionable grasp on the problem space. (Score:4, Insightful)
But all machines do that anyway. Ram runs at 1.5V or 1.8V, the CPU runs at 1.2ish these days. Where does that come from? 3.3V or 5V rails..
This is why people are moving everything to the 12V rail on the PSU (ATX12V standard and other ideas) A single efficient conversion with a local on-board conversion is best.
DC power still has a lot of other issues.
Best way to save energy on web servers... (Score:2, Insightful)
Heat, or heat pump? (Score:1, Insightful)
Well I live in Canada, and most people I know use electric heating. Yes, central electric heating is great, and actually cheaper than oil around here. (Montreal area)
Putting aside the fact that burning hundred-dollar bills is a cheaper source of heat than oil these days, are you sure you're not talking about heat pumps (air conditioners that can run "backwards"?)
Heat pumps are by far the most efficient way to warm a building using electricity; everyone I know who uses "electric heat" actually has a heat pump that will switch over to resistance heat only as a backup.