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Facebook Putting Batteries On-Board Its Servers 155

Posted by kdawson
from the following-where-the-big-boys-lead dept.
1sockchuck writes "The data center of the future may have no central UPS units, and be filled with servers with on-board batteries. Facebook says it will adopt a new power distribution design that shifts the UPS and battery backup functions from the data center into the cabinet by adding a 12-volt battery to each server power supply, an approach pioneered by Google. Facebook says the move will slash its power bill and save millions in capital expenses on UPS systems and PDUs. Facebook acknowledged that these types of custom designs are limited to large companies, but called on server vendors and data center builders to adapt their offerings to make them available to smaller companies."
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Facebook Putting Batteries On-Board Its Servers

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  • by TheLink (130905) on Friday November 27, 2009 @02:04PM (#30247140) Journal
    From the article: "Facebook's new distribution scheme calls for 277 volt power to the servers. "We're working with power supply vendors to create a (server) power supply that will accept 277 volts on the input," said Michael."

    Why 277 volts?
    • Higher voltage means less amperage to run a server.

      • by ckaminski (82854)
        And why is that good? Is not the actual wattage math still turn out the same? So it doesn't impact your kilowatt/hours... Help the ignorant.
        • by PIBM (588930) on Friday November 27, 2009 @02:38PM (#30247452) Homepage

          The wiring resistance is constant per meter (for a given cost) and increasing the voltage will reduce the amperage, while the power loss in the wiring is the multiplication of the amp times resistance, so, by increasing the voltage, the reduce the amp which in turn reduce the power loss in the transmission.

          • Could you dumb it down a shade?

            • by RiotingPacifist (1228016) on Friday November 27, 2009 @02:58PM (#30247672)

              If you have bigger pick up trucks, then you need less of them to carry a set amount of goods and so there is less traffic on a road.

              • by LBt1st (709520)

                Thank you :)

                • by mrmeval (662166)

                  You can make the road wider for the same effect but consider that the road is made of copper and it's expensive and non-standard.

              • Re: (Score:3, Funny)

                by DarrenBaker (322210)

                Spare me your medical mumbo-jumbo. Say it in English, Doc!

                • by TheLink (130905)
                  Say you are using water power to spin something at a certain speed.

                  Voltage is like water pressure.

                  Amps is the amount of water flowing per second.

                  To transmit the same amount of power, you could have a thick pipe, low pressure and lot of water flowing. Or a skinny pipe, very high pressure and very little water flow (at the other end water at high pressure would be able to spin a turbine at the same speed as the low pressure water with lots of water despite there being a lot less water).
            • I don't think it can really be dumbed down more than he already has, except to say that it's more efficient to transmit the energy in high voltage, low amperage format. That's why mains power transmission lines are usually carrying thousands of volts, which gets gradually stepped down by transformers the closer it gets to your house. I can try reducing what he said to individual phrases and explain each one if you like....

              The wiring resistance is constant per meter (for a given cost)

              The amount of resistance

              • I wanted it dumbed down, not academicked up! It's OK, you were beaten to it by an automotive analogy.

              • by egarland (120202)
                It's more than this though. 277 volt is 3 phase power. Unlike your standard home wiring which is 1/2 phase, 3 phase power always has voltage on it somewhere. 1 or 2 phase power has times where it has no voltage and computers need constant power. Because of this, three phase power supplies shouldn't have to go through as much work to smooth out the output power they should be more efficient. I'm not sure about this because I can't find anyone selling them.
            • by Agripa (139780)

              The power loss is proportional to the square of the current so if you halve the current then the losses decrease to 1/4 of what they were.

              Power Loss = Current * Voltage Drop
              Voltage Drop = Current * Resistance

              Substituting:

              Power Loss = Current * Current * Resistance = Current^2 * Resistance

              This applies equally to AC and DC current unless the frequencies involved are high.

    • by Cassini2 (956052) on Friday November 27, 2009 @02:41PM (#30247486)

      277 (V) corresponds to the line to neutral voltage of a 480 (V), 4 wire power distribution system. 480 (V) systems are fairly common in industrial settings in the United States. The major disadvantage of using 480 (V) to power a server, is you can't use a UPS. UPS on 480 (V) systems are rare and expensive, hence the reason why Facebook wants the batteries inside the server.

      I'm pretty certain you really don't want to run servers from the 277 (V) line to neutral voltage of a 480 (V), 4 wire system (3 lives, one neutral). On a 4 wire system, you have 4 wires and you can lose any one of them. If you lose the neutral, your servers could be running of 480 (V) instead of 277 (V). They will be destroyed.

      Losing the neutral is a relatively common failure in 3 phase systems, as many 3 phase systems are 3 phase, 3 wire with a fake neutral/ground connection that is often mistaken for a neutral. This central connection is purely to prevent the 3-wire system from drifting off of off ground, like when lightening strikes, which is common in a big high-voltage system. When operating a 10,000 (V) to 480 (V) step down transformer (the transformers inside the metal fenced enclosures), a small amount of electric slippage to occur between the windings. 1% of 10,000 (V) is 100 (V). Faults can also occur in big loads, like motors. A 10% ground fault on a 480 (V) 400 (A) motor, could be 200 (V) at 40 (A). These voltages/powers are nothing for a 480 (V) motor, but are enough to cause significant damage in a computer with a 1.2 (V) processor. This mismatch is why you should never trust the ground/neutral connection on a high-voltage supply line. It is for safety, not for powering computer equipment, electronic equipment, and electronic motor drives. After having replaced tens of thousands of dollars of electronic motor drives, my rule is: make the supply 480 (V) 4 wire, and all the loads 480 (V) 3 wire. A 3 wire load with no neutral can withstand problems with the neutral. A 4-wire load powering electronics line-to-neutral will not withstand neutral failures.

      If you are going to use 480 (V), you really want to use 480 (V) 3 wire AC (3 live wires, no neutral). If any one power circuit is lost, nothing really bad happens. Also, power semiconductors are readily available for 480 (V), because all the industrial motor drives require them. As such, your power supply will be cheaper.

      • by rcw-home (122017)

        If any one power circuit is lost, nothing really bad happens.

        If by circuit you mean phase, then you never lose just one phase. Cutting one wire of a three-phase system leaves only one circuit, not two - two-thirds of your load circuits will not have power.

        I've seen the loss-of-neutral failure exactly once - an electrician was doing work on what he thought was a separate circuit, and disconnected the neutral to a live circuit (there might have been more to it than that, but that's what he confessed to doing

      • by jbengt (874751)

        The major disadvantage of using 480 (V) to power a server, is you can't use a UPS. UPS on 480 (V) systems are rare and expensive, hence the reason why Facebook wants the batteries inside the server.

        Rare and expensive for small systems maybe, but 480V UPSs are fairly common on the construction projects I've worked on, at least for larger systems.

        i'm pretty certain you really don't want to run servers from the 277 (V) line to neutral voltage of a 480 (V), 4 wire system (3 lives, one neutral). On a 4 wire system, you have 4 wires and you can lose any one of them. If you lose the neutral, your servers could be running of 480 (V) instead of 277 (V). They will be destroyed.

        Maybe I'm not that certain (being a mechanical engineer and not an electrical engineer), but if you lose the neutral on a circuit, you'll open the circuit and won't destroy anything. Anyway, 277V is pretty common for single phase loads like lighting in buildings where 480V 3Ph is available, why not for data centers?

    • by ThreeGigs (239452)

      Three-Phase power is generally cheaper when you're talking megawatts, and can be used more efficiently.

      Linkage:
      http://en.wikipedia.org/wiki/Three-phase_electric_power [wikipedia.org]

      A typical office building will use flourescent lighting based on 277 volt supply.
      (note the above applies only to the United States)

  • by hesaigo999ca (786966) on Friday November 27, 2009 @02:07PM (#30247178) Homepage Journal

    This right after they announced they were going public. This will definitely boost their stock price.
    I think facebook has some good merit, however I am an avid anti facebook poster boy when it comes to destroying
    relationships. If you thought it was easy before to hook up online and cheat on your spouse, well imagine now!!!

    Girlfriend: "Hey, i got over 5000 friends online, isn't it wonderful???"
    Boyfriend: "ummm...why are they all pictures of young good looking dudes wearing no shirts....?"
    Girlfriend: "well that's because you can put anything on there..."
    Boyfriend: "how long have you know these so called friends?"
    Girlfriend: "Well not long, most are people that invited me to be their friend"
    Boyfriend: "Why is this guy keep writing on your wall how hot you are....I am not sure i really like this..."
    Girlfriend: "You always make such a big deal about nothing..."

    • by Abstrackt (609015)

      This right after they announced they were going public. This will definitely boost their stock price.

      They never said they were going public, they just changed their share structure in such a way that can be construed as a precursor to an IPO.

      What they did say, however, is that using those batteries will save them a lot of money.

    • by gbjbaanb (229885)

      Thing is, boyfriend is jealous 'cos he doesn't have 5000 nubile teen girls as friends, whereas Girlfriend is just happy to get mindless attention from them, she's never going to meet any of those losers.

      The trick is just to relax about it all, if your gf flirts she could be unhappy with you and looking for an alternative (but she can do this silently too, and you should be able to tell anyway). If she does that and you let her, not only is she happy, calm and confident, but also she'll think you're great an

      • No ego has nothing to do with it dude, for me its about the respect.
        After (i wont go into long drawn out drama) I was told about her father cheating on her
        and how her mother turned out, and how she was scarred for life after that, I guess I expected a little more is all. Especially if I am constantly under close observation myself...
        and if I had 5000 friends that were girls with any remote semblance of beauty,
        it would be the end, so she says.

        So i really don't like it as someone in a relationship, but being

  • Oh good (Score:5, Funny)

    by ArchieBunker (132337) on Friday November 27, 2009 @02:10PM (#30247194) Homepage

    What would the world be like if facebook went offline... I'm not sure I could continue living.

    • It’s OK. You will become “an hero” then. :)
      Facebook users will finally love you then! ;)

    • by Minwee (522556)

      Don't worry. You could start a group called "Bring back Facebook!" and get everybody you know to join.

      I'm sure that would help somehow.

  • What about disposal? (Score:2, Interesting)

    by Turzyx (1462339)
    As a rough estimate I would say mission critical servers get changed out every 3, maybe 4 years. I would imagine any cells would need to be at least laptop battery sized to run the server for an appreciable period of time, so what is going to happen when a server gets replaced? Keep the battery? I don't think so.
    • by temojen (678985)

      System refresh rates vary by customer. I work at a subcontractor that does refresh installs among other things. Some companies it's every two years. Some companies are repairing mission-critical servers that are Pentium II's with OpenUnix.

      • That doesn't mean the refresh rate is acceptable. Pentium II systems still running today will likely have 2+ hard drive failures in their history and at some point buying the proprietary scsi-II drives becomes price prohibitive - if you can even find a replacement.

        I don't know exactly the point the GP was trying to make, but it sounds like adding batteries to a system would be either an eco-terrorist concern or a maintenance concern depending on the refresh cycle.

        • by temojen (678985) on Friday November 27, 2009 @06:29PM (#30249914) Journal

          Those Pentium IIs are what gives me something to do... so many break/fix calls between them and the same company's over-complicated network.

          My point was just that you can't assume everyone has the same refresh cycle, just like you shouldn't assume that all servers are in a datacentre, or that racks are only in a datacentre, or that all servers are on racks, etc. There's a lot of variety out there.

    • Batteries should be replaced every few years as well.
  • Since batteries have to be replaced every few years that will not be any fun taking those servers out of the racks one by one to replace their batteries. One would hope they'd be changeable from the back or front, but I wouldn't bet on it.

    Also, UPSs can be retained when you buy upgraded servers. But if it's built in, you get to buy it again.

    And capacity? You can't just get a bigger UPS to run longer on battery. Although if you have true external (genny) power you just need something to hold for the cuto

    • by 7213 (122294)

      If your operating a large scale data center and not replacing the SERVERS every few years..... your doing it wrong.

      • by JWSmythe (446288)

            I didn't replace my servers every year. I did cycle them down to lower priority uses though. :) We had some machines over 5 years old that were doing simpler lower priority tasks. There's no need to throw the equipment away every year, if you could recycle it to another use. Well, unless you have a huge budget, and like throwing money away. I always preferred to waste my budget on better stuff.

        • Re: (Score:3, Insightful)

          by PIBM (588930)

          Well, you need to take into account the full cost of ownership. Are those servers using 500W of power to run, doing 1/4th of the work of a new server requiring only 300W ? At 10c/kWh, it cost you 1500$ / year to keep them running not including the climatisation, beside the wasted space (4 times more than the newer servers), and you will not be able to sell them at a meaningfull value after too long.

          • by Leebert (1694) *

            Come again? 200W power difference.

            0.2 kW * (24 * 365)h * $0.1/kWh ~= $175.

            • by PIBM (588930)

              you get rid of 4 servers, putting it on that new one. 2KW -> 300W = 1.7KW saved.

              Recently removed 9 servers around here, replacing it with 2 for redundancy, 1 working the other duplicating, using 3.9KW/h less than the previous setup measured at the UPS entry point.

              The servers will be paid for in less than a year.

    • by ckaminski (82854)
      Most decent servers today come with hot-swap power supplies. Simply put your battery into that, and off you go. And if you've already switched to 12V DC in the datacenter, it's even better! No costly AC/DC conversion at the 100's of points of use.
    • This has been common place on IBM equipment for years.

      That last machine had batteries on each of i/o controllers (RAID) with dual memory cards so that card system can take a "hit" and even half the i/o controller could go, and you can still change the I/O controller and KEEP the data in transaction.

      The cabinet itself had dual power supplies with batteries, each board used dual power from dual supplies. The cabinet took two 30A 480V 3-phase feeds, and supplied 400V DC to the boards, which then dropped the p

  • "mesh" thinking (Score:3, Interesting)

    by girlintraining (1395911) on Friday November 27, 2009 @02:16PM (#30247260)

    The problem with mesh computing is that it doesn't save in energy costs. With a centralized UPS and power supply, improving efficiency requires that you upgrade one unit. This way, you have to upgrade a few hundred units. It's similar to why moving to electric cars is advocated despite their limited range and low performance: Because it's easier to upgrade a dozen power plants than a few hundred thousand cars, to take advantage of the latest technology.

    • by sjames (1099)

      Unfortunately, that UPS is intrinsically less efficient. Resistive losses keep you from just provisioning 12 VDC to the racks, so you have a DC power supply feeding batteries which feed an inverter (to produce the same AC standard as the input) which then provisions power to the racks. That inverter will never be 100% efficient, nor will the power supply.

      The server power supply with built-in UPS skips those two losses. The power supply already has to rectify 100-220VAC into 12VDC (or actually a bit above th

      • by drsmithy (35869)

        Loosing one server is no fun, but you should already have plans for that. Losing a centralized UPS is a real problem! ALL servers go down then, even if the power didn't fail (someone will have to manually switch to bypass)!

        No they don't, because your servers have dual power supplies, with each PSU on a different circuit.

        Right ?

        • by sjames (1099)

          It can be done, but in practice I rarely see it.

          I also saw a case where a room did have twio independent systems. Then an electrician managed to connect a hot from A to a hot from B and the whole room went down, UPSs and all. It seems there was a single point of failure after all.

          A UPS per server is looking better all tghe time.

          • by drsmithy (35869)

            It can be done, but in practice I rarely see it.

            Say what ? What kind of worthless colo facility doesn't have at least two independent, redundant power circuits to each rack, and why would anyone be doing business with them ?

            Heck, even if you're self-hosting, you should have one PSU hanging of the UPS and the other wired directly to the mains. That will protect you from nearly all "expected" power-related failures.

            • by sjames (1099)

              and why would anyone be doing business with them ?

              Because they're affordable. The vast majority of websites don't bring in a bazillion megabucks a second and would rather risk the occasional brief outage than double the infrastructure cost.

              In other cases, they already have a failover facility elsewhere .

              The nice thing about the built-in UPS is that it can provide the same benefits as multiple UPS and multiple circuits without the cost.

  • The Voltage is not the problem, it is the Ampere Hours(AH). It can be achieved but there is a hidden problem of replacing the batteries after their Charge/Discharge cycle makes them ready for replacement. Say in about 3-4 Years, Facebook will die because of their Servers crashing out, one by one, if Battery condition is not monitored? Google may help, i definitely can.
    • Re: (Score:3, Insightful)

      by sjames (1099)

      Why do you assume that the in-server batteries will be completely ignored but a central UPS will be meticulously maintained?

      • by rcw-home (122017)
        Google and Facebook would meticulously ignore both (unless by "central" you mean "powers the whole datacenter"). That's the whole point of designing your software to withstand some of your servers going offline at any time.
  • The best solution? (Score:4, Interesting)

    by LWATCDR (28044) on Friday November 27, 2009 @02:20PM (#30247298) Homepage Journal

    This is interesting to me in a couple of ways.
    The idea is that it is cheaper to have just a battery instead of a UPS. A UPS will also have to have an inverter.
    Okay I can see this but they why have it at the server level?
    Remove the power supply from the server and put it at the rack level? Have a big redundant power supply for each rack and batteries for each rack?
    Or why not use DC for the entire data center and put the battery at the Data Center level?
    Seems to me that there may be more than one way to skin this cat and each have it's pluses. If you are using a large number of low load balanced servers where having any one go down isn't a disaster then putting the battery on the server would give you a good trade off. You are probably more likely to have a single server to fail than a more centralized system would but the odds of taking down the system would be tiny.
    I would love to see a study of the benefits of each type of system with the trade offs.

    • by Necroman (61604)

      I know my company has looked into this somewhat. Thinking about putting an inverter at the rack level and supply DC power to all of the systems on the rack (we make hardware). This would move the power supplies out of individual system to the rack.

      • by LWATCDR (28044)

        Put a battery in the mix and you have a power supply with an integrated UPS. Add in a small micro-controller that can connect to Ethernet and you now have a network managed power distribution system. Wouldn't be to hard to allow individuals to toggle power to individual servers.

    • Re: (Score:2, Informative)

      Or why not use DC for the entire data center and put the battery at the Data Center level?

      12VDC, each unit needs 300W at least... That's 25 amps per unit. Think wire gauge [windsun.com]. That's the reason, long and short. That, and you can't run 12VDC very far before power loss becomes a significant consideration.

      Tesla figured this out over a hundred years ago -- AC powers and transformers = more efficient.

      • by LWATCDR (28044)

        Actually they run DC data centers at telco voltage levels which is a believe 48 volts. Since you are only sending power hundreds of feet and not miles the losses and wire gauge involved are not that bad. Now if you put the put the power supply at the rack level then you could run 12 volt to the servers.
        BTW phone exchanges traditionally ran on 48 volt DC so those systems are mature to say the least.

      • by Agripa (139780)

        12VDC, each unit needs 300W at least... That's 25 amps per unit. Think wire gauge. That's the reason, long and short. That, and you can't run 12VDC very far before power loss becomes a significant consideration.

        DC distribution for telecommunication tends to be -48 volts DC and is designed to run with a 48 volt battery in a wired-or configuration.

        The most significant DC distribution systems for computers are based on 370 volts DC which allows low power operation directly from a 120/240 volt AC rectifier prod

    • Re: (Score:3, Interesting)

      by hannson (1369413)
    • by ghostis (165022)

      Google is already doing server+plus battery in their shipping container-based data centers. They claim that their research shows that larger power supplies (rack or row or bigger) are much more efficient.

    • Re: (Score:3, Interesting)

      by inKubus (199753)

      If you read the Google stuff, they have a number of reasons for it. Firstly, they wanted to minimize or eliminate conversion costs (Converting AC to DC and vice versa takes energy, sometimes 10-20% right off the top in heat. Secondly, they didn't want to have to do standard systems planning to deploy more capacity. With a central UPS, you have to worry about how many systems are plugged in, how many VA, etc. You have to do these calcuations and planning all the time with new hardware configurations. Go

  • by Fishbulb (32296) on Friday November 27, 2009 @02:22PM (#30247316)

    Distributed!
    Centralized!
    Distributed!
    Centralized!
    Distr...

    ad infinitum

    • by dave420 (699308)
      Because technology changes frequently. It's the same with parallel versus serial - at some points in history technology leans towards on being superior for given uses, and at other times the other is.
    • BOTH!
      And other options. With gray areas in-between
      And other dimensions. With different amounts of orthogonality!
      And with scales relative to the observer!
      And not a point, but a volume inside them.

      HA! Stupid box can’t keep me from thinking freely!

  • by SuperBanana (662181) on Friday November 27, 2009 @02:28PM (#30247360)

    Facebook says the move will slash its power bill and save millions in capital expenses on UPS systems and PDUs.

    And it'll move the complexity and unreliability to the server. The whole idea behind centralized UPS's (and by the way, you still need PDUs) is that you have reliability, serviceability, and economies of scale and efficiency. Now you have to monitor and service the batteries in thousands of pieces of equipment. And guess what happens when one of those batteries fails by getting cooked? Sulfuric acid all over the place (yes, even the "sealed" lead acid batteries can fail and leak) instead of the batteries being in, say, a battery room. God help us if they use lithium-ion, which would introduce us to a world of server fires and water damage, since a lot of datacenters are now dry-pipe to save costs. Nevermind that batteries and their associated electronics take up space, and that space has to come from somewhere.

    So, now you have each server getting more expensive, more complex with both hardware and software (server now needs its own battery power management) heavier, bigger, featuring toxic materials, and now non-standard, non-commodity design which vendors will charge more for as they specialize the equipment.

    I'm sure this all looks great on a powerpoint slide simplified into "if we put batteries in our servers, we can throw out our expensive UPS and save money!" This is just another hot/stupid trend; just because Google is doing it, doesn't make it brilliant. I stopped believing everything google was doing was a Best Practice around the same time gmail started going down for hours (and for some users, more than a day) at a time on a regular basis. [google.com]

    I tuned out of the article around the point where the guy from Facebook complains about cosmetic features interfering with airflow. Uh, guess what, bud? Dell's pretty front panel has been optional (saving you a few bucks sometimes) for years.

    • by ThreeGigs (239452) on Friday November 27, 2009 @03:02PM (#30247726)

      Another idea behind a UPS is _a_single_point_of_failure_. Moving the power backups to the individual servers eliminates that worry. Plus, since the servers are already redundant, you don't need the redundancy on the UPS, inverters, etc., which should save money.
      And since it's long-term, I'm willing to wager it won't be lead-acid, but NiMH. So no real maintenance issues. And your "what happens if..." scenarios apply equally to a battery in a megawatt UPS or a battery in a server.
      As for battery management and 'specialized' power supplies, etc.: go check out a laptop. That wheel has already been invented, and better yet, has benefitted from mass-production.

      • Another idea behind a UPS is _a_single_point_of_failure_. Moving the power backups to the individual servers eliminates that worry.

        Large-scale UPS systems are generally built with excessive amounts of redundancy.

        Plus, since the servers are already redundant, you don't need the redundancy on the UPS, inverters, etc., which should save money.

        You're assuming the servers are redundant, and that there is zero potential for lost data. Even with that fancy software we saw a week or two ago, it was discuss

      • by rcw-home (122017)

        And since it's long-term, I'm willing to wager it won't be lead-acid, but NiMH. So no real maintenance issues.

        Google is definitely using lead-acid batteries - the same 12V sealed lead-acid batteries that would go in a small UPS, keycard system, fire alarm system, etc.

        As for maintenance, most lead-acid batteries last about 4 years, and both Google and Facebook are probably retiring their old hardware faster than that.

        As for containment on failure, I'd say that's a well-understood solved problem.

    • by jefu (53450)

      gmail started going down for hours (and for some users, more than a day) at a time on a regular basis.

      By "on a regular basis" do you mean twice (and unpredictably) in the last year or so?

  • Most servers sit there at 3% cpu until something strenuous occurs. You've still got the big fans blowing, drives spinning like mad, and lots of power getting sucked down. I'd like to be able to see these units able to reduce power in low-use times and seamlessly ramp up when demand hits. It bugs me that we leave servers running overnight at full clip simply because we don't want to come in early to turn them on for the early workers, don't trust they'll come back on after a powerdown due to IT voodoo, etc.

  • by Animats (122034) on Friday November 27, 2009 @02:38PM (#30247442) Homepage

    Facebook is also converting over to solid state drives. They will have relatively low power consumption per board. Putting both flash chips and a backup battery on each board makes sense.

  • This is idiotic. Why not just run the equipment on 48VDC (telco style) with extremely high efficiency DC SMPSes and heavy gauge wiring? Power that directly with a large bank of batteries.. no inverter.. no distributed battery mess (pressure discs do burst).. no capacity limits.. no server weight issues..

    Not to mention, under this scheme you can no longer fully de-energize the datacenter (or parts of it). An EPO switch could cut the mains, but I certainly wouldn't want thousands of fully-charged batteries

    • Run the servers on 240 (VAC) / 280 (VDC). Almost every computer power supply converts the incoming power 120/240 (VAC) into a 320 (V) or so internal bus via a voltage doubler for 120 (V), and a bridge rectifier circuit at 208-240 (V). This means with NO MODIFICATIONS you can power almost every single server on the market from 280 (VDC), with no problems. Additionally, you can use a few bridge rectifiers, which are very common and inexpensive parts, to automatically select from a 240 (VAC) line and a 280

  • by mhollis (727905) on Friday November 27, 2009 @02:45PM (#30247542) Journal

    I used to work at a company that decided to install large, monolithic UPS systems after the power company hit them with a spike that took the entire system down for over a half hour. As they're a broadcasting company, they (rightly) felt that feeding their network affiliates nothing was not a good idea.

    As a result, they have these UPS "rooms" that hum like the dickens when you're passing them in the hall, all with batteries that will need to be replaced regularly (just like the Google server battery systems, so it's the same problem no matter what). Reason for the hum?

    The hum is caused by these giant transformers that step the power from DC to AC and create 110 volts of AC current at whatever amperage is required for normal devices. But there is a lot of wasted energy in doing that.

    Computers and servers all run off of DC power. They plug into AC power and then run that AC through a "power supply" that converts that to DC that the computer can use. That takes power, but power is plentiful when it comes from the power company and you pay your bill on time. But when you take the power from the power company, then change it to DC to charge batteries and then take power from those batteries to change it to AC to power normal wall outlets only to take that through a server's power supply to change it to DC again for the computer to use it, you're looking at lots of wasted energy in just changing from AC to DC, back and then back again, as well as changing to the kind of voltage and amperage needed to run the microprocessor, power the memory and power the drive arrays.

    So this is all about lowering consumption. And if you lower consumption, you lower your electricity costs.

    The hobbyist magazines were all aflutter some years ago about using photovoltaic (solar) energy to power a house. But what everyone had to do (early on) was to change their appliances (or order special ones) to run on DC -- not because you couldn't make AC current from the DC output of the photovoltaic systems but because it took a lot of energy to do that and these hobbyists were all about trying to save so much energy that they could take themselves off the grid.

    Here, on a large scale, you see the same idea. It's just more efficient to do this. And one of the big arguments in the early years of electrification was between DC power distribution (Thomas Edison) and AC power distribution (George Westinghouse and Nikola Tesla). We may wind up fighting these battles again in the near future.

    • by evilviper (135110)

      The hum is caused by these giant transformers that step the power from DC to AC and create 110 volts of AC current at whatever amperage is required for normal devices. But there is a lot of wasted energy in doing that.

      That may be true in your case, however, there's no reason for AC/DC conversion to be inefficient. Shop around for AC inverters for solar installations and you'll find ~97% efficient units.

      APC did a study on the efficiency of AC vs. DC as well, which shows a bare minimum of extra efficiency to

  • Don't they require power too? It's all very well keeping your server up in the event of a power failure but unless you keep your routers (and the routers all the way to the backbone) up, what's the point?

  • by jandrese (485) <kensama@vt.edu> on Friday November 27, 2009 @03:01PM (#30247700) Homepage Journal
    I for one would be very interested in a standard for consumer UPSes that has them output 12v DC, and an ATX (or BTX) motherboard extension that allows it to take 12v DC in for its power needs. Failing that, a DC-DC power supply could be used.

    The point being that it's dumb that a UPS has to invert the power coming out of it just so the power supply can rectify it back to DC. I'd much prefer saving the step and running DC straight from the UPS to the motherboard.

    Come to think of it, the standard isn't necessary, a UPS manufacturer could do this today, although they would have to bundle the dummy power supply with the UPS. The cost could even be kept somewhat reasonable if you factor in the savings from not having to buy a power supply. The only major sticking point is that most UPS vendors put out a lot of distressingly bad products and the consumer trust issue will be a problem.
  • I remember seeing a power supply around 2004 that had one or more backup batteries that fit in trays in 5.25" drivebays so you could hot-swap them and they were internal to the server. A SOHO or retail server (for a handful of POS' ) with this and a couple of PCI multiport ethernet cards and a PCI docsis or DSL modem would do a lot to consolidate the IT equiplent and all it's power bricks and interconnections. Sadly I've not been able to find that type of power supply since.

  • Yes, computers operate on DC.

    Yes, putting a DC battery in between the DC output of the PSU and the DC input of the mobo will have a UPS / Laptop battery effect on temporary mains voltage loss.

    The problem is very few mobos only have 12VDC input. This won't take care of the vast majority of mobos that also require 5VDC

    5VDC isn't practicably doable from lead-acid @ around 2 VDC per cell.

    Yes, there are ways around this, but the only practical ones are external DC-DC conversion, *or* 12VDC only mobos, which use

  • ...that the central switch that goes out of the net, and some other small devices, have no internal UPS... ^^

    No use having all the servers still running, if the “glue” between them dies anyway.

  • My Farmville will be much more efficient!

    Not exactly sure what this will do to my vampire clan, though. Hmm...more energy?

  • by PPH (736903)

    ... already do this. There are power supplies available in various PC and rack form factors designed to run off of the 48Vdc CO battery.

    One thing to consider (and I'm sure Google and others have worked the economics) is the maintenance costs of a centralized battery bank vs distributed batteries. Batteries don't last forever and some types require periodic attention (topping off the electrolyte in lead acid cells comes to mind). Although monitoring functions have become increasingly automated, someone stil

  • Facebook says it will adopt a new power distribution design that shifts the UPS and battery backup functions from the data center into the cabinet by adding a 12-volt battery to each server power supply, an approach pioneered by Google.

    I hope facebook's lawyers know that Google has a patent application [uspto.gov] for this very idea. TFA didn't mention whether or not they are actually licensing these and other Google-patented techniques.

    • as/400's have had built in batteries since 1988. They provide about 20 minutes of processing time which allows you to gracefully bring the machine down.
  • How many betteries will they need and what is the ecological impact or recycle strategy and life span of said batteries ?? It seems that this might save in the short term but be a real mess in the long term.

  • If they're going to redesign the PSU and put it together again, maybe it's time to drop 12V. What components still require 12V other than optical drives, 3.5inch HDDs, and high end video cards? Those are all pretty much optional in servers like FB's.

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