What does the U mean in server racks? Size meaning explained

Server furniture is used to accommodate network equipment in data centers. When dealing with such constructions, it is important to consider dimensions thoroughly. The choice of proper server furniture size determines the durability and smoothness of IT system functioning.

“U” (unit) comes as one of the main dimensions of server furniture. Yet, it is the most complicated one since it requires particular attention and precise measuring. So, in this article, we’re going to provide you with an explanation to the question “What is U in server rack”.

The Meaning of “U” in Server Rack Name

First, let’s clarify what does the U mean in server racks. “U” is a dimension used for measuring the rack height. It stands for “unit”, where 1U is 1,75 inches. Thus, if you see such designations as “6U”, “22U”, etc. in the name of the rack model, it denotes the height of the server furniture.

The term “unit” (U) was promoted and introduced by Electronic Industries Association (EIA) to standardize furniture measurement.

Why is 1U taken for height measuring? The thing is that 1,75 inches is a common height of a server, meaning that a 1U rack can accommodate one server. Thus, the more Us the cabinet has, the more servers it can house.

Nowadays, manufacturers produce a wide range of models of different sizes. The height ranges from 1U to 48U.

Types of Server Furniture

According to the number of Us, models fall into three main categories. Here they are:

  1. Full enclosures. These are the largest possible models that can accommodate hundreds or thousands of hardware pieces. The most typical models range between 42U and 48U.
  2. Half racks. Half-sized models usually have a height of 22U or similar. They are suitable for network systems that do not need a lot of space. Mid-sized systems are perfectly housed in such products.
  3. Quarter models. This is the most compact type of enclosure. Such bodies are perfect for small premises and limited areas. The size range typically goes from 1U to 11U. If you have a small telecommunication system with a dozen of devices, this solution is handy and space-efficient.

The most common models of server furniture include 42U, 32U, 22U, 18U, 12U, 9U, and 6U. A 42u rack is a popular option for large-scale data cetres, while 6U is an excellent example of quarter product. You can buy all the mentioned models from Sysracks, a trusted supplier of server furniture. Experienced managers always help consumers to select suitable models for their systems and rooms. Models for any budget and taste are offered on the website.

Note that to calculate the height of the rack, you should multiply it by 1,75. For example, 6U is 10.5 inch-high, 22U is 38.5 inch-high, 42U is 73.5 inch-high, etc.

How to Calculate the Needed Height of the Server Rack?

Now, when we’re done with the server rack U meaning, let’s move on to the issue of how to calculate correctly what height of furniture you need. So, here’s a step-by-step guide:

  1. Count what number of servers you need. Each server needs a place of 1U.
  2. Make a list of other hardware pieces to be placed in the rack.
  3. Separate them into those that are taller than 1,75 inches and those that are smaller than 1,75 inches.
  4. Calculate how much space they will take. 3D visualization helps simplify this task and eliminate common mistakes. Take into account the possibility of hardware colocation. By creating a 3D layout, you’ll design the best equipment allocation in cabinets and calculate the optimal rack size needed to accommodate all devices.

Extra Issues to Keep in Mind

Apart from calculating physical software, it is necessary to think about some other issues. So, the below-listed points require particular consideration:

  1. Security. If your rack is placed in a public place, and it is difficult to limit access to devices, make sure to ensure a sufficient level of rack security. You may need a cage, in which you’ll put the rack for extra security. Or, think about other ways to protect hardware from intruders.
  2. Power draw. Make sure that the available PDU is able to supply the required amount of energy to feed your system. IT equipment is very energy-consuming, so calculate the required power to guarantee smooth powering.
  3. Maintenance. When making the layout, think about comfortable maintenance since the staff will face problems and have to disable the system to replace or maintain devices, if the layout is uncomfortable. Thus, place frequently maintained components closer to the opening, while rarely used ones go to the rear side.
  4. Expansion. Finally, look far into the future and foresee the need to add new components when the system requires extra power, capacity, and datum computing capabilities. Thus, it is advisable to choose a bigger model to leave free space for future upgrades.

Server furniture is a popular type of product since it is needed in any office, facility, or enterprise. Now, you know what is U in rack size and can calculate what furniture your business needs. So, you’ll succeed when picking appropriate models for your purpose.