Integrate: OpenRack

After Windmill and Watermark, the time was right another round of consolidation, bringing the rack design into the mix.

Dragonstone server renders

An issue with the Freedom servers was that the PSU was non-redundant (resulting in the Dragonstone design) and regularly had a larger power capacity than ever would be needed, which popped up on Facebook's efficiency radar. Adding another PSU in every server would mean an increased CAPEX and OPEX, because even when using an active/passive mode, the passive PSU is still using power.

A logical conclusion then was that this problem could not be solved within the server chassis, but could instead be solved by grouping power supplies of multiple servers. This resulted in OpenRack v1, a rack built with grouped power supplies on 'power shelves' supplying 12.5V DC for a 4.2kW 'power zone'. Each power zone has one power shelf (3 OpenUnits high), a highly available group of power supplies with a 5+1 redundancy feeding 10 OU (OpenU, 1 OU = 48mm) rack units of equipment. When power demand is low, a number of PSUs are automatically powered off allowing the remaining PSUs to operate much closer to their optimal points in the efficiency curve.

Another key improvement over regular racks was the power distribution system, which got rid of power cables and their need to be (dis)connected each time a server is serviced. Power is provided by three vertical power rails called a bus bar, with a rail segment for each power zone. After fitting each server with a bus bar connector, you can now simply slide in the server, the connector hot-plugs into the rail at the back, done. An additional 2 OU equipment bay was placed at the top for switching equipment.

Server Generations Mass Storage
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  • SuperVeloce - Wednesday, April 29, 2015 - link

    From Mass storage: "Compared to hard disks optical media touts greater reliability, with Blu-ray discs having a life expectancy of 50 years and some discs could even be able to live on for a century."

    Yeah sure. Like my expensive gold color cd's from different vendors, baked on different high quality writers, now mostly not working anymore after some 15-20 years. Despite being held in almost perfect environment all these years
  • Uplink10 - Wednesday, April 29, 2015 - link

    Someday they are going to figure out that:
    -SAS HDDs are costlier but if you are using RAID it does not matter, they should use consumer drives and not overpriced enterprise drives
    -I calculated sometimes back if Bluray cold storage is cheaper than HDDs but it is not and more so you cannot change the data once you write it, it is better to go with HDDs
  • toyotabedzrock - Wednesday, April 29, 2015 - link

    You have to wonder what these networking chip vendors are hiding in the firmware that makes them so resistant to open sourcing the code.
  • Casper42 - Monday, May 4, 2015 - link

    Johan, some of the HP info at the end was interesting, but incomplete.
    If you (or anyone reading this) plan to talk to HP, they will also talk about their relatively new CloudLine "CL" type machines as well.
    They come in standard 1RU/2RU designs as well as OpenRack designs coming soon.
    And the SL line is all being morphed over to Project Apollo which uses the XL prefix.
    Apollo 2500 is now live, 4X00 will replace SL4500, 6000 has already replaced S6500, and the 8000 was a net-new add for Gen9 focused on big HPC farms.
    So anything SL is, or soon will be, a dead platform. (The SLs you mention could be an exception since they are not widely commercially available)
  • Netpower - Tuesday, June 2, 2015 - link

    One general problem with this design is how to take care of power line disturbances entering the power shelves via the 277V AC lines. The 48V DC is filtered via the 48V battery but you must add a filter/power line conditioner somewhere to make sure that transients and sags doesn't kill your power shelves. The 380V DC approach by ( is much more reliable and still have all the advantages with higher efficiency, lower cable losses etc.
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