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Google Calls For Power Supply Design Changes
Raindance writes "The New York Times reports that Google is calling 'for a shift from multivoltage power supplies to a single 12-volt standard. Although voltage conversion would still take place on the PC motherboard, the simpler design of the new power supply would make it easier to achieve higher overall efficiencies ... The Google white paper argues that the opportunity for power savings is immense — by deploying the new power supplies in 100 million desktop PC's running eight hours a day, it will be possible to save 40 billion kilowatt-hours over three years, or more than $5 billion at California's energy rates.' This may have something to do with the electricity bill for Google's estimated 450,000 servers."
google hires experts on Electrical Engineering to figure out how to reduce the power bill on those 450,000 servers. Hell, I'm all for it. Less power means less heat means quieter fans (w/o spending an arm/leg on an Antec Sonata or whathaveyou).
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In the old days, disk drive motors and fans. But many of these now run on 5V, hence the cheap USB-powered drive cases out there. Chips at CMOS power levels run at 3.3v, TTL is 5v, but hardly anything runs at 12v anymore. It seems to me that if they'd just pick their hardware carfully, they could run their entire server rack off of 5v+- rails.
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I assume Google is employing some smart electrical engineers, which are more than qualified to make this kind of recommendations I would think...
-- the cake is a lie
Its a nice idea and one that is probably a long time coming, but phasing something like that into place will take an incredibly long time. Look at the struggles of PCI express, its still not in 50% of the newer motherboards and systems though its benefits are more than apparent. Its just been in the past couple years that we have seen a shift to full usb and most machines still come with ps2, serial and parallel ports anyway. Dramatic changes to the PC standards are very difficult, there are millions of existing machines that still need support. Perhaps if it was tied to a new socket standard in the future it could slowly be phased in through upgrades, but I see the chances as very very slim.
I would bet a lot of the employees at Google have Electrical Engineering degrees. Don't underestimate the brain power Google has in its employee base. But the power supply issue they're trying to address isn't a technical challenge, but a political challenge.
You can say goodbye to USB powered devices. An example would be the canned drink cooler.
Thanks,
Jim
For your 12 volt battery that can vary more than 10% as it discharges, you'll need something like what I have designed for use in cars. Some motherboard makers already make computers that run on 12 volts. The Commell LV-673NS Pentium M Mini-ITX Mainboard already runs on 12 volts (+- 5%), and then if you use the Mpegbox DSX12V which is 95+ efficient, then it can run off a battery or in a car.
The ability to have all my machines powered by a heavy cable carrying 12VDC would be pretty useful for several reasons.
*sigh*
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There is no reason to be annoyed by people trying to do good things!
Reality is nothing but a collective hunch.
The motherboard itself is an outdated concept. It's no longer really necessary if you've dealt with small form factor boards you can easily see that the boards are just a substrate to stick the chips on and for that a flat board-like surface doesn't make sense. What you really need is a cubic cartridge like device that gives you access to more surface area for interfaces close to the memory and CPUs and other chips in a smaller area. It would also facilitate cooling reducing power requirements at the system level.
n/m found it.
t e_paper.pdf
http://services.google.com/blog_resources/PSU_whi
I have been saying this for years. We lose 10-20 % of energy charging a battery in a UPS with 117V, we lose another 20-30% in the inverter to get it back to 117V, and then we lose another 10% getting the 117V back to usable voltages for the PC.
It does not take an expert in electrical engineering, just common sense.
Can I sue google for stealing my idea?
A lot of telco equipment is designed to run on -48 volts DC and PC and server power supplies are readily available at this voltage.
The advantage of -48 over 12 volts is that there will be less loss through resistance and smaller conductors can be used. Of course, there is a greater risk of electric shock, but I would think -48 would be pretty safe.
48 volts is also the standard for Power over Ethernet (IEEE 802.3af). This may not be compatible, though, since telcos run -48, not +48, though some equipment can operate with either (though some cannot).
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Google's whitepaper is interesting but the fact is that DC in the Datacenter is already happening, and it's not gaining much momentum for multiple reasons.
Google's perspective is rather unique, they use super-cheap desktop systems that individually do not use a lot of power and thus running them off 12v DC might make sense. But in any other, more conventional datacenter, servers have multiple power supplies that can EACH pull 800w of power. Now when you're running 110v AC that means you're pulling ~7 amps through a single cable. You need datacenter grade power cables for this, but it's still sane. Now you can get datacenter equipment that runs 48v DC, but those cables end up running ~15 amps through them, so now you need substantially stronger cable - cable so thick that running it becomes a seriously difficult task due to the guage of the wire!
More likely the direction people are going (and have been for some time) is to 208v AC or 3 phase 220v AC. Now you've just halved the current draw, meaning that your PDUs don't need to be as hefty, your wire doesn't have to be as thick, your coils don't get as hot, etc.
Running 12v DC in any real data center would be ludicrous - the amount of current you'd have to draw through your cables would be way beyond a safe level.
Also AC/DC conversions are cheap these days. And remember, DC can kill you just as easily as AC when your DC Voltage is that low.
"I want to get more into theory, because everything works in theory." -John Cash
Most of the postings so far have it all wrong. Google is not proposing 12VDC into a desktop PC or 12VDC distribution within the data center. What they're proposing is that the only DC voltage distributed around a computer case should be 12VDC. Any other voltages needed would be converted on the board that needed it.
This is called "point of load conversion", and involves small switching regulators near each load. Here's a tutorial on point of load power conversion.
It's been a long time since CPUs ran directly from the +5 supply. There's already point of load conversion on the motherboard near the CPU. Google just wants to make that work off the +12 supply, and get rid of the current +5/-5/+12/-12 output set.
They're not talking about reducing the voltage the PS uses, they're talking about not having the PS produce things like +5 and -5 as well as +12, INSIDE the computer.
Many recent motherboard use 12V to control voltage regulators' MOSFETs gates because the higher the voltage, the lower the internal resistance, so the higher the efficiency. 5V is generally too low to achieve good efficiency, but 12V is fine.
From 12V, the MB can produce 3.3V and 1.xxx Volt for the CPU. It's easy to also provide 5V on the MB.
The Mac Mini will boot and run on a 12-volt supply. It only takes 17v so that it can provide Firewire power.
-jcr
The only title of honor that a tyrant can grant is "Enemy of the State."
Not quite on topic but..
It amazes me that so few people realize that a "nominal" 24V is the norm for all manufacturing. Just about EVERY manufacturing plant has 24V throughout the facility, they may (or may not) also have 120/240, but they WILL have 24V - amps and amps of the stuff.
This means there's a full range of 24V equipment, millions of devices. 24V PC's, 24V hubs/switch and all the other infrastructure as well as specialized industrial controllers, etc. etc..
There's some logic behind this that doesn't related to power saving, mainly that you really have to work at doing yourself serious injury with 24V, but you can still pull enough power to run things (like PCs).
Having this low voltage standard is very useful, but before we consider adding another, how about just considering using the one that already exists.
Sco's lawyers might be out of a job soon. I'm sure they'd love to help!
Reality is nothing but a collective hunch.
Google is proposing 12V between the server's internal power supply and the motherboard. Everything outside the server would still be 208V.
I agree that a standardized 12VDC connector on all electronic devices would be nice, like every other poster here has pointed out, but I don't think that is what google is talking about. You can already get power supplies that take 12VDC in, or even dual 48VDC (telecom standard), and I would be surprised if google isn't using something like that already.
What they are recommending is that the power supply only have 12V out, and all other DC-DC conversions take place on the mother board. Unfortunately, the article didn't go into any detail as to how this would save power, and I don't see how it would make much difference. To me it just seems like you are moving components off the PS and onto the motherboard. Perhaps there is an EE around who could explain it to me.
Their answer is the Petabox. It's a server setup designed to be "shipping-contained friendly", meaning they can build out a container stuffed with these racks, and have it operational on site with connections for power, cooling, and bandwidth. With this design, they can deploy a mirror of the Internet Archive anywhere that's willing to host it, without having to build a machine room or individual racks on site.
Capricorn Tech of San Francisco builds these machines and their site has more info.
--Pat
Oh. So, we have lots of switching power supplies and tantalum capacitors (because we have to supply lots of current at low-voltage) on the MB. Thus moving work from a cheap part of the computer to an expensive part. Not sure I want more power-supply electronics on the MB than is already there.
Bruce Perens.
>>If you put a massive AC-DC transfomer in another area
Why do I suddenly see an image of a giant robot wearing a schoolboy uniform, playing an electric guitar?
Serial remains one of the most manageable approaches to console management. Video is, obviously, not loggable, not automatically monitorable, not greppable, and not amenable to low throughput, high latency remote access.. Serial devices and consequently drivers for them are so simple and straightforward, and the behavior so deterministic, that it is far preferable to something more complex (ethernet and usb) for a console. Ethernet certainly in questionable circumstances may suggest a driver unload/reload as a step to problem resolution, which is safer if not using as a console (though many times I have used ssh and chained the commands using semicolons). For example in that case, if your path contains an nfs mount, and you forget about it as you yank the network out, your chained command will hang as the shell tries to stat the nfs mount for the path. Part of the problem with relying solely upon the ethernet for console is the ethernet has more than one job to do, so it takes a fair amount more competent engineering to get to work right. Many newer systems offer to redirect textual serial traffic over IPMI, and that is admittedly decent *if* the vendor architects it robustly, which is difficult to ensure beyond hands-on experience with a brand and trusting in their consistancy. For example, e326 servers from IBM I wouldn't trust the net console, but an IBM x3455 I would be more confident in. USB, again, has similar complexity issues (it's multiplexed for keyboard/mouse/mass/storage/printing/scanning/etc etc). If you theoretically had bi-directional text console over some usb device, it's more difficult for a low level, simple piece of software to set up the usb controller and all requisite activities, then traverse the bus, identify the console devices, and then use it. Just like with an ethernet device where you may have cause to unload and reload a driver, a usb controller out to lunch with respect to a mass storage device would cause a similar issue. Enterprise distribution kernels tend to compile in the serial console and leave the usb controller modular, specifically with serial consoles in mind.
Serial console servers, in answer to your question, provide a scalable way for systems to access via the network serial consoles. By being dedicated, moderately simple systems with 40+ serial cables, they can provide access (via telnet generally) to a rack's worth of 1U servers, automatically log the content, or at the very least provide an administrator with remote console access at will to any given system.
Serial console is not obsolete in the least bit, just because it can't run your '31337' aero interface, or whatever nice and shiny interface that makes poser administrators and PHBs drool, doesn't mean good, serious systems administrators don't consider the technology to be a vital part of a robust management strategy.
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I wouldn't count on it. When you're buying in quantities as large as Google is there is no small chance that they designed thier own motherboard and case specifically for their purposes. There's no point getting the floppy controller, USB, and any of the other stuff that you normally get (even on server machines) that's totally useless to Google. They probably paid a lot of attention to the power consumption, not only to install the smallest reliable power supply possible, but also to figure out how many they can cram into a rack and how much power/cooling they'll need.
I read the internet for the articles.
if you have to re-convert anyway, 5V as intermediate voltage is not optimal. When converting to 5V, the voltage drop in the power diodes and in the wires to the mainboard eats a much higher proportion of the power than with 12V as intermediate voltage. 24V or even 48V would be even better.
Telephony has been running on redundant -48V DC supplies to the racks (typically from rooms full of floating storage batteries) since the early relay days. Much modern networking equipment also conforms to this standard, so it can be used in such racks with no local power supply (except the per-card isolation diodes and downconverters).
Power conversion modules running from 48V are in volume production.
Why does Google want to reinvent this wheel?
(However, if they do insist on using 12v, I hope they make it able to work from 11.75v to about 15V, with glitches, and shut off at stable levels below 11.75v. That way such boards could be used directly with 12v renewable energy systems, plugged directly into an automobile "cigarette lighter" power outlet, or easily wired into a vehicle or travel trailer as an appliance.)
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For efficiency, CPUs are heading below 3.3v, and RAM too.
That's actually why single-voltage PSUs make sense. Your CPU, GPU, and RAM don't care if the PSU is providing 12V, -12V, 5V, or 3.3V, or any combination of them, as long as its VRM steps it down to the 1.7V or whatever it needs. So why have the power supply provide so many different types of power, instead of just one of them? It's all going to be converted by a local VRM anyway.
And a single-voltage power supply is about 85% energy-efficient at converting AC power, compared with about 65% for four-voltage (12, -12, 5, and 3.3) supplies, due to various redundancies. Switiching to all 12V means you've made the power supply less complicated, more efficient, and less expensive, at the cost of a few extra VRMs on any 5v and 3.3v components that are put in the machine.
There are over 6500 Walmart stores with an average size of 120000 square feet. Every 500 sqaure feet they have a 4-tube fluorescent light fixture, drawing 4x40 or 160 watts. Multiplying out, the total square footage is ~6500*120000=780,000,000 square feet. Divide by 500 square feet to get the total number of fixtures, 1,560,000, and multiply that by 160 watts to get the total watts, 249,600,000. Probably 75% of those Walmart stores are 24 hour, while the rest are 12 hour: (.75*24)+(.25*12) = 21 average hours
.068 = $130,096,512 per year in electricity.
Total Watts x Avg hours x 365 days per year = Wh per year
249,600,000W x 21h x 365d = 1,913,184,000,000 Wh per year
Wh/1000 (kWh) x the going rate (approximately 6.8 cents nationwide)
1,913,184,000 x
If they took out one tube per fixture, they would save $32,524,128 per year.
*This doesn't include the parking lots, which have a similar consumption.
So, what's the point? There are other, easier ways to save a lot of power. I'm glad Google wants to change the computer world, but what about replacing 10% of the incandescent bulbs with fluorescents and save 50W x 10,000,000,000? Or just TURN OFF your computer when you aren't using it! Retooling the entire industry would cost MORE than it would save in power. That's not to say I don't agree that we need to start making a lot of little changes and this is as good a place as any. But the benefits are very far in the future, when we run out of oil. Not now.
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There are different kinds of UPSes that do this in different ways. The two major types used for PCs are called "line interactive offline" and "dual conversion online". The first just passes the AC power straight through to the output. If the AC power coming in goes out of range, then it flips a switch internally (relay, contactor, thyristor, etc) to supply the power from an inverter driven by the battery. The second converts the AC coming in to DC all the time, and converts that DC back to AC for output. It then does the switching in DC, or parallels the DC with the battery directly. These variations are classified as "topology" by many manufacturers.
Both of these kinds can have inverters that produce square waves, pseudo-sine waves, or very nice clean sine waves. The dual conversion type can also isolate a poor power factor (the deviation of the current wavefrom from being a sine wave in sync with the voltage) of the PC power supply from the power source. A poor power factor means the product of the average current times the average voltage (apparent power) exceeds the actual real power (average of all the products of the voltage and current and each point in time) being used, which results in reduced efficiency and other problems.
now we need to go OSS in diesel cars
Another way to get more efficiency is to operate the Switched-mode power supply at the higher voltage it supports, usually 220 to 250 volts. In most of the world this is already done. In North America computers are typically run on 120 volts (in Japan this is 100 volts). In general, these power supplies are more efficient by about 3% or so, on the higher voltage. Of course, be sure to flip the voltage switch if it has one, or otherwise verify that it does support the higher voltage.
For a single computer, it would not be worth adding the extra circuit to get 240 volts. But if you run several, it could be worth doing so, especially if you have so many that it exceeds the capacity of one 120 volt 15 or 20 amp circuit (you could have twice as many on the same amperage if operating at 240 volts). If you already have a circuit dedicated to the computers, that circuit could be converted from 120 volts to 240 volts by changing out the circuit breaker from a one pole to a two pole type, marking the white neutral wire with red or black tape to comply with electrical code identification requirements, attaching these wires to that new breaker (not to the neutral bus), and installing a 240 volt style outlet (NEMA 6-15R or 6-20R). These are the steps that would be used to install an outlet for a big window air conditioner (which you might need anyway with so many computers). Then you can use this power cord.
now we need to go OSS in diesel cars
Ach, shoot, we spent it on USB ports. Never mind.