'Power Capping' the Datacenter

snydeq writes "Datacenter operators seeking increased server density may soon turn to power capping, an emerging technology that limits the amount of electricity a server can consume, InfoWorld reports. The practice, which can be applied at the rack level, ensures that no server draws above a set power level, thereby increasing datacenter capacity within a rack-level power envelope by as much as 20 percent, according to a proof-of-concept study at Baidu, China's largest search company. As with powering down servers during off hours, of course, power capping incurs calculated risk, as those in charge of business-critical applications may be reluctant to set power limits below maximum utilization. Yet given IT's need to contend with the permanent energy crisis, the notion of power capping the datacenter could prove advantageous."

Comments

How long until..

[Rayeth]

One only wonders how long it will be until every spreadsheet process becomes "business critical" to override restrictions such as this.

Not a crisis

[tsotha]

"Permanent energy crisis"? There's no such thing as a permanent crisis. Yes, energy costs are going up because we're more sensitive to the impact of new capacity. But that hardly constitutes a crisis. The word "crisis" has been practically stripped of meaning - everything these days is a goddamn crisis. When the girlfriend you were about to dump gets pregnant - that's a crisis. A few bucks more on your energy bill - not a crisis.

Re:Not a crisis

[tsotha]

Sigh. I understand all that, but the numbers are hardly insurmountable, or even very uncomfortable. How many nuclear power plants could we have built for the trillion dollars we spent on "stimulus"? Four or five in every state, by my calculations. The idea that everything is just going to fall apart when the price of oil goes up is just silly.

Re:Not a crisis

[FooAtWFU]

The Stone Age didn't end because they ran out of stone. The Oil Age might end when we start to run low on oil, but that doesn't mean we won't have plenty of alternatives.

The economic argument for all sorts of magic coming from having oil traded in USD is weak. A barrel of oil is worth whatever the next buyer things a barrel of oil is worth, a dollar is worth whatever the next guy who gets it thinks it's worth. These things are both fungible, they're both pretty liquid. There's a vibrant currency exchange market. If people think the dollar or the barrel-o-crude is not worth what it used to be, the prices are perfectly capable of shifting to match. Look at the last big recession and oil crisis of the 1980s. Look at 2008, for crying out loud. The US dollar may wax and wane, the US economy may shrink 10% in a bad year, but oil dropped from over $100 a barrel to something like $30.

As for the money supply, the Federal Reserve is pretty capable of generating as much or as little of our little fiat currency as they feel like. The national debt (and the price at which people are willing to buy it worldwide) is what's going to be weighing on the US and its economy over the next several decades, much more than any medium-of-exchange games. The government and the private sector compete for loans: when there's more debt, it's more expensive for private firms to borrow and that hurts economic growth - because look! Treasury bonds! They're nice and safe. Why would you invest in a risky old Business in /this/ economy?

Just a friendlier name for...

[clarkcox3]

Ins't this just putting a friendlier name on "overselling"?

• We can pack in 20% more boxes because we don't really have the power to meet demand should all of them spike at once, but that doesn't usually happen.
• We can sell in 20% more airline seats because we don't really have the room to meet demand should all of the customers actually show up, but that doesn't usually happen.
• We can claim unlimited bandwidth, because we don't really have the capacity to meat demand should all of our customers actually download 24/7, but that doesn't usually happen.
• etc. etc. etc.

Re:Just a friendlier name for...

[frosty_tsm]

It depends what they are overselling and to what degree. Overselling a plane screws whoever is left behind (large impact over small set of customers). Overselling bandwidth slows someone's download or game (small impact over many customers).

Overselling a rack and causing servers to a) fail or b) corrupt data costs in hundreds of thousands or more pretty quickly in damages and legal fees. It's a much wiser business decision to just increase the power capacity (not that some suits will think this is the greatest thing since cloud computing).

Re:Just a friendlier name for...

[Anonymous Coward]

Yes, and it is that kind of amoral and unethical crap that is giving the shaft to the consumer day after day after day.

You're right! Gyms, for example, shouldn't sell memberships to more people than they can fit in the gym at the same time. Otherwise, if every one of their members decided to go to the gym at once, they'd have to turn some away!

(Seriously - overselling is just another risk. Taking no risks is bad. Taking too much risk is bad.)

Our Policy

[teknopurge]

I can't see any legitimate provider capping power usage. We have 20A running to a client rack by default - if they need more circuits we charge them per circuit. The only place I can see people wanting to make an argument for capping power usage is if a provider has oversold their power infrastructure and is starting to feel the pinch because they're not charging enough. Same goes for bandwidth: if you want to price things cheaper and cheaper to attract customer, I believe it';s unethical to then raise rates after-the-fact because of poor planning/forecasting.

Re:Our Policy

[Wesley Felter]

Power capping is intended to be used by the server owner; e.g. in a colo that would be the customer, not the provider. You give the customer a circuit and they use capping to fit as many servers as possible on it.

Mechanical batteries

[copponex]

Beacon Power is an American corporation specializing in flywheel based energy storage headquartered in Tyngsboro, Massachusetts. Beacon designs and develops products aimed at utility frequency regulation for power grid operations. The storage systems are designed to help utilities match supply with varying demand by storing excess power in arrays of 2,800-pound (1,300 kg) flywheels at off-peak times for use during peak demand.

http://en.wikipedia.org/wiki/Beacon_Power

The people who keep saying we can't find ways to be more efficient should stop wasting oxygen.

Another way to overcharge smaller users

[khodsden]

This happens to be why my quarter rack space has only 2 1U computers in it. It was supposed to be a quarter rack (10U), but I was told I had only 7U of space. Okay, not a problem, I can put in 7 1U systems, 14 if I purchase the half sized systems. Then I was told I have only 2A, oh, and here's a switch that'll turn it off if you go over. Which means my quarter rack has two 1U servers in it.

Worse, even the full rack is allowed only 15A before you have to buy a secondary power conduit to the rack at this particular colo.

I suspect it's more a way for the facility to make money than it is to reduce energy usage. When I visited the facility last to move boxes, 4 racks were being emptied and a good 60% of them were completely empty anyway, so the facility may not be long in this economy.
 

Re:Metered datacenter?

[afidel]

Basically every colo datacenter is metered. Standard is 2x20A circuits (16A max draw) per rack. If you want 30A or quad 20A circuits in your rack you generally pay a hefty overage charge. At our DR colo provider they require metered PDU's. I have this capping capability with my HP servers which means I can fill a rack right up to the edge but make sure I don't overload the circuit by keeping my peak usage closer to average. You also need to use staggered startup on your servers if you want to play it that close to your power cap.