Types of Racks in Data Centers: Rack vs. Shelf vs. Cabinet vs. Suite

Different Types of Data Center Racks

When you are looking to invest in Boston colocation services or rent servers from a secure datacenter, you will have the choice between racks, shelves, drawers, cabinets, cages, and suites. You may be left wondering, what’s the difference between these data center rack types?

Our colocation and remote backup professionals offer all these space options at our own Boston data center. So, we know a thing or two about what separates a rack from a shelf, a cabinet from a cage, and everything in between.

One thing you should know is that the main difference between all these rack types is their size. Below is a list of the different types of racks in a data center and more about server rack sizes.

Rack & Rack Unit “U”

A server rack is an open frame designed for mounting multiple electronic equipment modules to hold servers and IT equipment. The width and depth of standard data center racks slightly vary by manufacturer, but the industry standard is 19 inches wide and 36 inches deep.

A rack Unit is the smallest measurement of data center space, typically referred to as “U”. This is used to measure the height of a server rack, one “U” is 1.75 inches high. One “U” represents one slice of rack or cabinet space. Colocation providers will typically offer server rack space designated with one or more U’s – 1U, 2U, 3U, 4U, etc.


Server cabinets are like racks in that they can hold multiple modules for electronic equipment. The main difference between a cabinet and a rack is that racks are open and have no sidewalls, while cabinets are enclosed on all sides. A server rack or cabinet encloser measuring around 20U or 24U is considered a standard half rack or half cabinet, while a 42U server rack or cabinet is the standard full-size rack or full cabinet.


A server rack shelf is an open shelf designed to be mounted within a server rack frame. Shelves are utilized to organize servers as well as other network and IT equipment. Secured on either 2 or 4 posts, server rack shelves come in multiple designs including fixed, sliding, vented, or solid shelves.

Rack drawers are similar to shelves in that they can be mounted within a rack, but they are enclosed boxes designed to store loose equipment, files, and helpful tools. Available in locking and non-locking options, drawers are not designed for servers and connected IT equipment.


A data center cage is a metal wire enclosure that can store multiple racks and cabinets. Made up of metal bars and metal mesh walls for maximum cooling efficiency, cages can either be shared or private. A private cage will only hold servers and IT equipment of one company, while shared cages are used by multiple companies. Colocation providers typically rent out cage space by the square foot instead of “U”.

Data center suites canalso hold multiple racks and cabinets. Suites are secure and fully enclosed just like cages but are more like private rooms separated by solid or glass walls on all four sides. Private suites offer unmatched customization, many of them are custom built to a client’s unique specifications and include features like office space (desks, printers, tables, etc.) plus other amenities.

Different Types of Server Racks 
Server Rack
%Rack Unit "U"
Server Cabinet
Rack Shelf
Rack Drawer
Data Center Cage 
Data Center Suite

At LightWave Networks, we offer multiple colocation space rentals at varying price points and sizes. We offer cabinets, racks, cages, and other data center storage options starting at $50 per month. Learn more by calling (617) 459-4100 today!

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