Rack vs Cage vs Suite vs Bespoke: which is better in a colocation data centre?

Dec 27, 2020
author logo

If you are considering renting servers from a data centre or investing in colocation services, you need to select between data centre racks, suites, cages, cabinets, and drawers. This may lead to you research the differences between these types of data centre racks. Majorly, the chief differentiating factor is size.


Here, we talk about the various server and data centre racks types to help you make an informed choice.


Server Rack


Server racks are open frames built for mounting several modules of electronic equipment to hold IT devices and servers. Each manufacturer makes data centre racks with varying depth and width, but the standard size is 36 inches in depth and 19 inches in width.


Rack Unit 'U'


A single rack unit is termed 'U', and it is the smallest measurement of data centre space. It is utilized to gauge a server rack's height - one 'U' indicates a height of 1.75 inches.


A single 'U' represents a single slice of cabinet or rack space. Colocation vendors offer server rack spaces with one or multiple U's, based on the requirements




A server cabinet is comparable to a rack as it can also hold several electronic equipment modules. The chief difference between the two is that cabinets are closed on all sides while racks do not have any sidewalls and are open. A cabinet encloser or server rack of 24U size is termed a half cabinet or half rack, and a 42U cabinet or server rack is considered a regular full-size cabinet or rack.




An open shelf in a rack is mounted in the rack frame. You can use shelves to organize IT and network equipment and servers. Shelves are secured on two or four posts and are available in several designs, including solid, vented, sliding, and fixed.


Rack Drawer


A rack drawer is similar to a shelf as it can also be mounted inside a rack. However, a rack drawer is an enclosed box that is built to store tools, files, and loose equipment. You can find non-locking or locking rack drawers, and they are not constructed for servers or connected IT devices.




Data centre cages are metal enclosures that can house multiple cabinets and racks. They are made of metal mesh walls and bars to maximize cooling efficiency. A cage can be private or shared. Private cages hold the IT equipment and servers of only one client (business), and shared cages can be utilized by multiple firms. Colocation vendors rent out space in cages by the square foot and not by "U".




A data centre suite also holds multiple cabinets and racks. It is secure and enclosed fully like cages. However, suites can be compared to private rooms that are separated by glass and solid walls on four sides. A private suite offers good customization. It is custom-designed for a client's exclusive specifications and offers features such as office space (tables, desks, printers, etc.) and other facilities.


Cages, Racks, Cabinets, and 'U's


Data centre cabinets look like large lockers, and they are similar to racks built with 19" internal width. The cabinet depth varies by maker, and the common measurements are 36 and 42 inches. Some racks come with just one mounting point on a side, which is located in the rack's centre and is termed as a 2 post rack.


On the other hand, cabinets have a 4 post setup with one pair of posts in the front and the other one in the rear. Racks are generally used only within private cages, so you'll get cabinet space if you're not looking to buy a cage.


Colocation vendors that offer shared cabinet use will give you space in one or multiple 'U's, as well as rack-ready devices and equipment built to function with these sections. While buying equipment, you'll see that the equipment chassis has form factor designations ranging from 1U to multiple 'U's. This tells you the needed cabinet space to accommodate the unit. You can determine your total space requirements by simply adding up all your devices' form factors.


With complete know-how of different data centre rack and storage types, make an educated decision and buy suitable storage space at STT GDC India for your IT equipment based on your unique needs. Besides, our multi-layered physical security provides secured access backed with round-the-clock CCTV surveillance - You can trust our capabilities!