A question we sometimes get from customers is, "What is a '1U' server?" "What is a '2U' server? What is the difference?"
The 'U' in any server description is short for "RU" which stands for Rack Unit -- this is the standardized designation for the form factor of the server:
- 1U = 1.75" in height or thickness.
- 2U is 1.75" x2 = 3.5 inches.
- All rackmount servers are 19" in width.
Additionally, since a U is 1.75", you can understand the rack server dimensions of equipment noted as "3U," "4U," and so on, as illustrated by the table below:
|
Rack Units |
Height (in) |
Height (cm) |
|
1U |
1.75″ |
4.4 cm |
|
2U |
3.5″ |
8.9 cm |
|
3U |
5.25″ |
13.3 cm |
|
4U |
7″ |
17.78 cm |
Note: as this is a standard, these designations apply to other rack-mountable equipment, such as network switches, firewalls, or UPS units.
Virtually all the Dell PowerEdge Servers and HP ProLiant Servers that TechMikeNY resells are either 1U or 2U. Here is a breakdown some of our popular models into their form factor bucket:
Dell 1U Servers:
PowerEdge R420, R430, R620, R630
Dell 2U Servers:
PowerEdge R720, R730, R820, R830
HP 1U Servers:
ProLiant DL360 G8, DL360 G9
HP 2U Servers:
ProLiant DL380 G8, DL380 G9
A helpful tip: both Dell and HP keep a consistency of the form factors within their models. For example, a Dell PowerEdge R600 series server will always be a 1U regardless of its generation (R610 vs. R620 vs. R630 = all 1U).