The physical server can be divided into three categories according to the inadequate shape -tower server, rack server, and blade server. The main differences between them are as follows:

　　Tower server

　　The tower server is a kind of server that everyone is common and the easier to understand and cognitive. The shape and structure of the tower server are not much different from the ordinary desktop computers used in our daily life.

　　Because the tower server is relatively extended, there are more slots, which causes the volume of the tower server to be larger than that of ordinary motherboards. Generally, there will be sufficient internal space to facilitate the redundant expansion of the hard disk and power supply in the future. Based on the above points, the tower server has a relatively wide range of applications and has become the most useful server. In daily applications, the tower server gathers a variety of common services. Applications in storage can be solved with tower servers.

　　Rack server

　　From the perspective of the server, the rack server is not like a computer, but like a switch. According to the difference in the height of the server, the rack server is divided into 1u (1u = 1.75 inches = 4.445cm), 2U, 3U, 4U, 8U and other standards. Generally speaking, the 1U rack server is the most space -saving, but it is relatively poor in terms of performance and scalability, and it is suitable for enterprises with relatively fixed business. The rack server above 4U has good extension performance. It can support more than 4 high -performance processors and a large number of standard hot plug -in components. It is very convenient to manage and suitable for applications with large visits. The disadvantage is that large volume, spatial utilization rate not tall.

　　Blade server

　　The blade in the blade server actually refers to the system motherboard. The blade server is to install multiple card -type server units in a standard height rack chassis. The purpose of this is to achieve the high density and high availability of the rack. The blade server can start its own operating system through the "board" hard disk, such as Windows NT/2000, Linux, etc. It is equivalent to independent servers. Therefore, in this mode System, serving different user groups, which also causes the blade -type server to have a low performance of single -piece maternal board compared to rack -type and tower servers.

　　However, this problem can also be solved. Administrators can gather these motherboards with only system software to become a cluster of a server. In the cluster mode, all the motherboards provide a high -speed network environment and can share resources at the same time to serve the same user. In addition, inserting a new blade in the cluster can improve the overall performance, because each blade is hot insertion, so it can easily replace the system and shorten the time to maintain the server.