When hosting servers or renting racks in a data center, you may hear terms like 1U, 2U, 4U, or 42U. Below is a brief introduction to the common rack U standards in data centers.


About the "U" Unit


U is an abbreviation for unit, a unit of measurement for the external dimensions of servers. Defining the server's dimensions allows it to be mounted on a rack with specific spacing. The rack features screw holes for securing the servers, aligning with the server's screw holes, and then tightened with screws for secure installation. This makes it easy to accommodate the space required for each server.


2U, 4U, 5U, 6U, and 10U server rack space hosting


The server specifications are defined by the server's width (48.26cm = 19 inches) and height (multiples of 4.445cm), with thickness (height) measured in 4.445cm increments.



Section 3: Standard Server Cabinet Rental


Standard racks for operators are typically 42U racks.


1) Available in widths of 600mm and 800mm for 42U racks, depths include 600mm, 800mm, 900mm, 960mm, 1000mm, 1100mm, 1200mm, and more.


2) In terms of customization: Besides the standard 42U rack space, width and depth can be tailored to your specific requirements.


The number of servers that can fit into a cabinet is limited. A 42U cabinet does not necessarily mean it can accommodate 42 1U servers. After placing the servers, space must be reserved for cooling, movement, cable routing, and additional room for devices like switches, firewalls, and monitors. Therefore, the number of servers a 42U cabinet can hold depends on the specific equipment. Now, the question arises: how many server devices are typically deployed in a single cabinet?


The number of servers that can be housed in a server rack depends on numerous factors, such as the physical parameters like server size, power consumption, and heat dissipation. Additionally, considerations must be given to the power supply, cooling, and load-bearing capabilities of the rack. To determine the capacity of servers that can be deployed, the following key parameters can be referenced when making decisions:


1) Reserve: Allocate 1U space between each device for ventilation, plan for switch placement, and consider the PDU location.


2) Generally, we provide a redundant 10KW power supply with a static load-bearing capacity of no less than 1200kg (determined by the data center construction parameters).


Under the condition of not exceeding the power supply, the cumulative U count of equipment in a cabinet usually does not exceed 26U.


A cabinet typically accommodates no more than 16 1U devices, 12 2U devices, and 4 to 7 4U devices.