Terminology for Servers, Racks, and Rack Mounts

  1. Aisle Arrangement: What is Aisle Pitch?
    In any data center, aisle arrangement is an important necessity to assist with data center cooling and air flow. “There are many factors that go into the design of data center space,” says Data Center professional, Vincent Fava. “Aisle pitch is...
  2. What is a button mount?
    IT professionals in Data Centers are looking for more tool-less options for speeding up the mounting process. Button mounts have become more and more common on server racks by several well-known manufacturers. Button mounts serve as a tool-less metho...
  3. What is a white box server?
    A white box server refers to customized servers that are either home built, or built by white box suppliers called ODMs (Original Design Manufacturers) such as Supermicro.  The term white box simply means that the equipment is unbranded or generic. ...
  4. What is OCP? (Open Compute Project)
    What is the Open Compute Project The Open Compute Project started in 2011 and stems from Facebook’s initiative to improve energy efficiency, reduce hardware costs, and speed up deployment, by developing their own custom servers, power supplies, ser...
  5. Ask Katrina- 19″ Rack & U Space
    In this segment of Ask Katrina, she answers FAQ about 19″ racks: Question 1: What is a “U space”? A “U” or “RU” is a unit of measurement that is commonly referred to when discussing rack-mounting equipment. A “U space” is 1.75 ...
  6. Define: VESA Monitor Mount
    What is VESA? VESA is an acronym for Video Electronics Standards Association. The current documentation can be purchased through the VESA organization. Overview Monitor and Video Display manufacturers produce their products to meet an industry stand...
  7. Define: Rack Hole Types
    Overview The hole types for racks have changed over time and varies from manufacturer to manufacturer and from application to application. Rack hole type is referenced in the EIA-310 rack specification. However, there is no one hole type that is con...
  8. Define: Rack Upright Shape
    Most server racks have 4 vertical uprights. These uprights (aka Rack Rails or Mounting Posts) have mounting holes on standard EIA spacing and are used to attach equipment. There are three types of uprights: “L”, “C” and R...
  9. Define: Rack Screws (10-32, 12-24, M6)
    Description Rack screws are used to attach equipment to the vertical uprights of a 19″ rack. Racks do not have a standard thread type. There are three common thread types for rack screws: 10-32, 12-24 and M6. Since the introduction of the s...
  10. Define: Rack Mounting Depth
    Overview Rack mount depth is a commonly confused term. The term is commonly confused with the overall rack depth including the door. The term is defined as the dimension from the front of the front mounting post to the back of the back mounting pos...
  11. Define: EIA-310
    What is EIA EIA stands for the Electronic Industries Association. The current revision is EIA-310-D. The EIA-310 document is available for purchase at the IHS website. Overview EIA-310 is a specification for what is often called the “standard r...
  12. Define: Big 3
    Definition In terms of servers and racks, the Big 3 refers to Dell, HP and IBM. These three OEM’s define the future trends in server form, fit and function. Their advances in terms of racks and rail designs have also changed the landscape of r...
  13. Define: Fixed Rails
    Description Fixed rails can most easily described as not a sliding rail or telescoping rails. Telescopic sliding rail kits provide the functionality of a drawer, more or less. The server can be pulled out of the rack and serviced without discon...
  14. Define: Rack Unit “U” or “RU”
    Definition The hole spacing for standard 19″ racks on the mounting flange is spaced in groups of three holes. This three hole group is defined as a Rack Unit (RU) or sometimes just call a “U”. 1U occupies 1.75″ (44.45 mm) of ...
  15. Define: Rack Types
    Description: The following is a list of the various types of 19″ Racks available: Server Racks (aka cabinet racks, equipment racks, 4Post racks) Open Frame racks (aka 4post racks) 2Post (aka Relay racks, Telco racks) Transport racks Portable r...
  16. Define: Shoulder Screws & Nuts
    Description: Shoulder Screws & Nuts are a piece of hardware that Dell typically uses to attach the slide rail kits to the chassis. The shoulder of the hardware drops into a notch on the inner tract of the slide rail assembly. This makes the ins...
  17. Define: Filler Panels or Blanking Panel
    Description A filler panel is a flat piece of metal that matches the Rack Unit (1.75″) of a Server Rack. Typical sizes range from 1 – 8 Rack Units. Filler panels are used to close the openings that are not being used in a Server Rack. Th...
  18. Define: 19″ Rack
    Description: The funny thing is . . . Nothing on a 19″ Rack measures 19 inches. The term 19 inch comes from the width of the front panel of the boxes that are installed in the rack (see the image below). To determine if your rack is a 19̸...
  19. Define: Tower to Rack Conversion Kits
    Description: A Tower to Rack Conversion Kit is a product that is used to convert a Tower Server into a Rackmount Server. This Kit typically contains a set of slide rails and a replacement front faceplate and bezel. The differences between the facep...
  20. Define: Cagenut?
    One of the biggest questions we get is “What is a Cage Nut?” Allow me to help out with this issue. A Cage Nut is used on a rack that has square mounting holes. You would use a cage nut when you need to mount a product in your rack that re...
  21. Acoustical Noise Emissions
    Servers are loud because they are loaded with cooling fans that pump as much air through them as possible. Sound is measured in Bels or the more common unit decibels, which is 10 Bels. The Bel is measured on a logarithmic scale. An increase in 3dB...