1U - 7U
The 1U, 2U, 3U, 4U, 5U, 6U and 7U are all different sized
rackmount servers; the U following the number is short for unit. The number indicates
the size of the rackmount, 1U being the smallest rackmount and 7U being the biggest rackmount. Below is a listing of each of the different units and
their dimensions, although the Width and
Height of a rackmount may be standard, the
depth of a rackmount may change, as can be seen below. If your rackmount server is going
to be placed in a constrained area, it's best to verify with the manufacturer of the rackmount what the exact dimensions are. In the picture to
the right, is a picture Courtesy of Dell Inc. of some of the Dell PowerEdge servers and examples of different rackmount
units.
| Unit | Dimension (W x H x D) |
|---|---|
| 1U | 19" x 1.75" x 17.7" 19" x 1.75" x 19.7" 19" x 1.75" x 21.5" |
| 2U | 19" x 3.5" x 17.7" 19" x 3.5" x 20.9" 19" x 3.5" x 24" |
| 3U | 17.1" x 5.1" x 25.5" |
| 4U | 19" x 7" x 17.8" 19" x 7" x 26.4" |
| 5U | 19" x 8.34" x 19.67" 19.1" x 8.75" x 26.4" |
| 6U | 19" x 10.5" x 19.5" |
| 7U | 17" x 12.2" x 19.8" |
Most collocations and ISPs accept 1U, 2U or 5U chassis; however, it is still a good idea to check with whomever is planning to host your server to verify what they support and at what cost.
Also see: Chassis, Network definitions