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Open Compute Developing Wider Rack Standard 237

1sockchuck writes "Are you ready for wider servers? The Open Compute Project today shared details on Open Rack, a new standard for hyperscale data centers, which will feature 21-inch server slots, rather than the traditional 19 inches. "We are ditching the 19-inch rack standard," said Facebook's Frank Frankovsky, who said the wider design offered better heat removal and a unified approach to power, including a 12 volt busbar. The Open Compute Project, developed by Facebook to advance open source hardware design, believes an open approach can avoid the mistakes of blade server chassis design."
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Open Compute Developing Wider Rack Standard

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  • by alphatel ( 1450715 ) * on Thursday May 03, 2012 @10:57AM (#39878403)
    So put the server power supply on the outside, basically.
  • by darthcamaro ( 735685 ) on Thursday May 03, 2012 @11:06AM (#39878513)
    There is a big distinction that you need to understand here, the Width of the Server chassis is changing, not the width of the rack itself. The outer dimension of the Server Rack is staying at 24 inches. The REAL problem was a bogus amount of extra cruft in the rack design that is going to be eliminated to make way for the wider servers.
  • by Anonymous Coward on Thursday May 03, 2012 @11:32AM (#39878891)

    12V DC is a great idea. Eliminate the power supplies inside each individual server and run the entire data center off one massive PSU.

    No, it's a stupid idea thought up by people who are ignorant in matters of distributing electricity. When you reduce voltage you increase amperage, there's no free lunch. Running bus bars around rated in the thousands of amps and up to distribute 12VDC is ridiculously stupid.

  • by IGnatius T Foobar ( 4328 ) on Thursday May 03, 2012 @12:16PM (#39879415) Homepage Journal
    That "extra cruft in rack design" is where your cables go. I have an 18,000 sqft data center over here and I can tell you from experience that what you call "cruft" isn't nearly enough space for all of the cables once things start getting dense. We are actually considering 23" (telecom standard) racks with 19" rails in them for cabinets that aggregate the networking gear, just for this reason.

    But oh no, far be it from Facebook to actually work with the industry. They screwed up the Internet and now they're going to screw up your data center.
  • by gstrickler ( 920733 ) on Thursday May 03, 2012 @12:27PM (#39879517)

    The spec can be downloaded from here [opencompute.org]

    At first, I thought this sounded like a stupid idea too. Then, I read the spec. They're not just changing the width of the equipment area, and it's not just an extra 2".

    External width is unchanged from the 19" rack standard, it's still nominally 23.6". No replacement of floor tiles or room redesign necessary.

    Equipment width is increased from ~17" (on a 19" rack) to 21", it's allows 4" wider equip.

    Power is handled in 3 "zones" per tower. Each power zone provides 12.5V DC power on each of 3 independent pairs of power rails, No AC power supply is required for each piece of equipment, but they will need DC-DC converters and VRs to supply the voltages needed for their specific components. That saves some space on each device, and provides a slight improvement in efficiency. Because this is standardized worldwide, there is no need for each device to have different power circuitry for different countries.

    Because a zone can have triple power rails, devices can use 1, 2, or 3 power rails to provide whatever level of redundancy is appropriate.

    Space for switches is included in each rack, along with power monitoring/reporting circuitry per rack.

    Battery backup power can either be built into the power supply for each zone, or supplied from a separate battery rack.

    The specification allows for many AC or DC power sources, this is the only significant part of the spec that will vary by country as the power units will need to support the available AC and/or DC supply.

    All devices are to be hot-plug compatible.

    So, it does have a lot of advantages.

    Here are the concerns I have with it:

    All power rails appear to be exposed. While they are on the back, this could be a significant safety (personnel and/or fire) issue. Considering that you can up to 500A @ 12.5V DC running through the zone power rails, and potentially more for the main cabinet DC power rails, exposed seems like a bad idea.

    The standard allows depths from 36" to 48". With the way devices connect to power rails on the back, it looks like this means you will need to use devices designed for the specific depth of your rack, or use a shim to extend the device to match the depth of the rack. I believe they should standardize on one, or at most 3 depths, and have a standard set of shims to connect the devices designed for the shorter depths to fit the deeper racks.

  • by Doc Hopper ( 59070 ) <slashdot@barnson.org> on Thursday May 03, 2012 @12:30PM (#39879579) Homepage Journal

    That's covered in the article. 21" racks within the current 24" standard rack size. By eliminating cable mass in favor of bus-bars, you gain the two inches "free" in your rack footprint. If the rack's designed right, you could even keep the same seismic bracing.

  • Re:metric? (Score:3, Informative)

    by ChatHuant ( 801522 ) on Thursday May 03, 2012 @01:27PM (#39880053)

    The Mars Climate Orbiter was a case of someone not labeling their units. The unit system wasn't the problem.

    But units wouldn't need to be labeled if everybody used the same system. The continued existence of the zombie Imperial system is the root cause of the problem.

    Secondly SI isn't always the best unit of measurement for performing calculations. In plasma physics we use eV in stead of joules for energy because it simplifies our work. In astro physics measuring distances in the SI unit of length, the meter, is impractical

    Which is why SI has a number of accepted units [nist.gov]. You'll note that both the eV and the astronomical unit are there, but not the feet or yards used by Lockheed to send a rocket past Mars.

  • Touching the 12Vdc @ 500A copper bar bus will kill off some of the new guard too.

    How? Are you trying to tell me that those 500A will run inside a person's body when you apply 12V of potential diference on it? You mean a person's body has 24m Ohm of total resistance?

    The 48V bus would kill much more people, even if less current flowed through it. A person only needs a few mA to die.

Where it is a duty to worship the sun it is pretty sure to be a crime to examine the laws of heat. -- Christopher Morley