subject: Understanding Server Types: Tower, Rack and Blade [print this page] Understanding Server Types: Tower, Rack and Blade
Selecting the best server for your needs can be daunting. Whether you are looking to build a small computing infrastructure for your home or home office, or you are tasked with improving IT functions for a large corporation, you have many options for servers from which to choose. It helps, therefore, to first understand the three basic server types -- tower, rack and blade -- to more easily narrow down which will best serve your needs.
Tower Servers
Tower servers are likely the most easily identifiable for the regular computer user. As the name implies, tower servers are housed in the familiar looking "tower" or case we associate with desktop computers. Like the desktop, everything associated with running the server is housed in this case power, cooling, chips, motherboards, etc. These servers are commonly used by homes and organizations seeking a server environment for smaller business functions. This does not mean, however, that these are not powerful servers. It is, however, easier to set-up and run, requiring less planning or "architecture" than the rack or blade server. For a business whose needs extend to one or a few servers, this may be ideal. However, a tower server's size becomes an issue for environments which require multiple servers or who have limited space. As self-contained units, tower servers take up more room. Therefore, scalability is limited by a person or organization's storage space.
Rack Servers
Rack servers are small, slim servers stored in racks. This storage method allows for vertical storage, therefore allowing for the use of multiple servers while requiring considerably less floor space than multiple tower servers. While an individual rack server might be less powerful than an individual tower server, the ability to use more of these servers in any one space generally provides more power overall. According to Hewlett Packard, rack servers are ideal for data centers and external storage, offering "maximum computing space in a space saving design." This design allows for easier scalability as well as cable and server management. In addition to holding servers, these racks can hold other hardware like backup and storage devices, maximizing your storage space. Concerns with rack servers are the difficulty inherent in cooling multiple closely-spaced, running devices.
Blade Servers
Similar to rack servers, blade servers' small size allow for the use of multiple servers while requiring less floor space and allowing easier scalability than tower servers. Unlike the other two servers, however, blade servers have had many of their components removed. Components which are normally built into individual tower or rack servers to provide things like cooling, ventilation, power, networking, etc, are instead shared among blade servers in an enclosure, allowing for more management, energy and space efficiency. Additionally, with multiple servers enclosed in one space, this allows for better redundancy and the ability to remove or swap one server without disrupting service. Blade servers do require more planning and technical skills than your basic servers, and typically can be more costly initially than tower or rack servers.
