What do 1U, 2U and 4U of the server mean?

When renting servers or cabinets , Sometimes I hear 1U、2U、4U perhaps 42U And other nouns like this , And what do these nouns mean ？

Rack servers don't look like computers , And like switches , Yes 1U（1U=1.75 Inch ）、2U、4U Equal specification . Rack servers are installed on standard 19 In the cabinet . This kind of structure is mostly functional server .

One 、 About “U” The unit of

U Is a unit that represents the external dimensions of a server , yes unit The abbreviation of . Specifies the size of the server , The server can be placed on the rack in a certain size . There are screw holes for fixing the server on the rack , So that it can match the server's screw hole , Fix it with screws , In this way, you can easily install the space required by each server .

Two 、1U The server 、2U The server 、4U The server

The specified size of the server is the width of the server （48.26cm=19 Inch ） With Gao （4.445cm Multiple ）, The thickness of the （ Height ）） With 4.445cm Is the basic unit .

In the rack server size , Common is 1U The server 、2U The server 、4U The server , The size of these servers is ：1U=4.445 centimeter ,2U=4.445*2=8.89 centimeter ,4U=4.445*4=17.78 centimeter .

In actual use ,1U perhaps 2U Servers are the most frequently used . Because the service provider calculates the cost according to the space occupied by the server , So using 1U The server is the most space-saving and the lowest price , but 1U The scalability of the server is not as good as 2U The server is good .1U The maximum number of hard disks can be plugged in 4 individual ,2U You can plug in 8 individual . in addition ,PCI The number of slots is also different ,1U most 2 individual ,2U You can go to 6 individual .

U Is the height of the server chassis 1U be equal to 4.45 centimeter , that 3U Namely 3x4.5CM 了 .

U(unit The abbreviation of ) Is a unit that represents the external dimensions of the combined rack , The detailed dimensions are provided by the American Electronics Industry Association as an industry group （EIA） decision .

EIA, namely Electronic Industries Alliance Electronic Industry Association , One of the standard setters in the American electronics industry .EIA（ Electronic Industry Association ） Founded in 1924 year , It was called the radio Manufacturers Association （Radio Manufacturers' Association：RMA）, Only 17 Members of the team , But 200 The radio manufacturing industry with an output value of 10000 US dollars . now ,EIA Members have exceeded 500 name , On behalf of the United States 2000 With an output value of billion US dollars, the electronic industry manufacturer has become a purely service-oriented National Trade Organization , Headquartered in Arlington, Virginia .

EIA Widely represents the design and production of electronic components 、 parts 、 Manufacturers of communication systems and equipment industry 、 The interests of the government and users , It has played an important role in improving the competitiveness of American manufacturers .

The specified size is wide （48.26cm＝19 Inch ） With Gao （4.445cm Multiple ）.

The thickness is 4.445cm Is the basic unit .

Server size specification ：

1U=4.45cm

2U=4.45cm * 2

3U=4.45cm * 3

4U=4.45cm * 4

U It's not the patent of the server , It was originally a rack structure for communication switching , The backup refers to the rack of the server . Currently used as an informal standard on rack structure , Including the specified screw size 、 Hole spacing 、 Track drawing, etc .

1U and 2U, Is the thickness of the server ,1U It's probably equivalent to two small grids of the cabinet ,2U It's four squares .1U yes 4.445 centimeter . Here is a picture ：

3、 ... and 、19 Inch

19 Inch standard cabinet ,19 It represents the width , Is that you can put 19 Inch rack server cabinet .

19 Inches is the width of the server , What size does it specifically refer to ？19 Inch =48.26cm, It refers to the distance between two lugs of rack type equipment .

The structure of standard cabinet is relatively simple , It mainly includes the basic framework 、 Internal support system 、 Wiring system 、 Ventilation system .19 Inch standard cabinet has width 、 Height 、 Three conventional indicators of depth . Although for 19 The installation width of inch panel equipment is 465.1mm, However, the common products of the physical width of the cabinet are 600mm and 800mm Two kinds of .

The height is generally from 0.7M-2.4M, Common finished products 19 The height of the cabinet is 1.6M and 2M. The depth of the cabinet is generally from 450mm-1000mm, It depends on the size of the equipment in the cabinet , Usually, manufacturers can also customize products with special depth , Common finished products 19 Inch cabinet depth is 450mm、600mm、800mm、900mm、1000mm.

19 The height occupied by equipment installation in inch standard cabinet is a special unit "U" Express ,1U=44.45mm. Use 19 The equipment panel of inch standard cabinet is generally according to nU Manufactured according to the specifications . For some non-standard equipment , Most of them can be installed through additional adapter baffle 19 Inch chassis and fixed . The panel width of many engineering grade equipment is 19 " , therefore 19 Inch cabinet is the most common standard cabinet .

Four 、42U Cabinet

42U The general classification of cabinets is ：

1） Divide by width ：600mm and 800mm Wide 42U Cabinet ;

The depth is ：600mm、800mm、900mm、960mm、1000mm、1100mm、1200mm etc. .

2） According to the actual demand ： Except that the actual size is 42U outside , The width and depth can be customized according to the actual needs .

The number of servers in one cabinet is limited ,42U The height of the cabinet does not mean that it can actually hold 42 individual 1U The server . After the server is placed, there is still room for cooling and moving , Some space for routing , And put the switch 、 A firewall 、 Space for monitors and other devices . therefore , One 42U How many servers can the cabinet hold , It needs to be calculated according to the specific equipment .