Rack mount enclosures, rack mount cabinets, server racks, what does all this mean? In most cases these terms refer to a convenient way to organize and store multiple computers (servers) or other types of computer equipment. These rack mount enclosures offer an effective way to store a large volume of computers in areas that offer limited space.
With all of these server cabinets being available in so many sizes and all those options that are available to the end user, there’s no wonder why there isn’t more confusion then there already is on which rack mount cabinet to choose from, so let’s start with some basics.
The most common type of rack mount cabinet is known as the “EIA standard” or 19-inch rack mount cabinet”. Most rack mount computer equipment is what we call a “standardized” 19 inch width. The internal width of these rack mount enclosures is the “EIA standard” of 19 inches, so when you are trying to determine how many servers and shelves you want your server rack to contain, they will all be in this standardized 19 inch format.
All computer heights are measured in units called “U’s”. Now don’t feel bad, this took me a bit to catch on to this concept too. When I went to school everything was either measured in inches or centimeters, but when working with rack mount enclosures things are done just a little differently. In the world of computers, when referring to the height of a computer, 1 “U” equals 1.75 inches. So when shopping for rack mount cabinets you will see references to cabinets like 10u, 12u, 25u and so on. So what does all of this mean to you? There are obviously hundreds of different sizes of server racks and multiple choices of shelving systems that can be put in to these rack mount enclosures. So in order to determine how much space is available for equipment and shelving options, the cabinets are rated in U’s.
For example: If I am looking at a rack mount cabinet that has a rating of say 25u. I of course need to choose some shelving that will fit into this cabinet for my specific application. So how do I know how many shelves I can fit in to my new rack mount cabinet? Well you will also find that the shelves for these cabinets are also rated in U’s. If I choose shelving that has a rating of 5 U’s, then this particular server rack that is rated at 25 U’s will accommodate 5 shelves. Because each shelf takes up the space of 5 U’s inside the rack mount enclosure. If I choose shelves that have a rating of 12 U’s each, then this rack mount enclosure will only accommodate 2 of these shelves. Once you catch on to this new concept of measurement it really does become quite easy to use and understand.
Airflow is always an issue when it comes to rack mount cabinets. Computers produce a lot of heat when operating, so dissipating this heat becomes critical when storing multiples of these devices inside of a single cabinet. This is certainly something you will need to take in to consideration when purchasing your server rack cabinet. You will also want to consider noise and cable management as well when making your purchase. All of these issues and more will be covered in future articles.
The cabinet of a computer is a tall movable closet used to house multiple computers and computer equipment. The form of the modern cabinet is standardized by the Electronic Industries Alliance, so that equipment can be placed in any manufacturer’s cabinet. The primary design criteria are:
1. Access to equipment – various kinds of locks and latches restrict access.
2. Airflow – Cabinets are designed to be placed side-to-side, so airflow is vertical, with vents and mounting brackets for fans.
3. Mounting Brackets – Mounting brackets have mounting holes at standard spacing and are a standard distance apart, to allow a variety of equipment to be installed in several configurations.
4. Grounding – The mounting brackets are conductive, acting as grounding strips for the cabinet and equipment, allowing the whole cabinet to be connected to the building ground.
5. Cable Access – The bottom of the cabinet is usually open, allowing external cables to drop through a raised floor.
(Noise reduction is built into some cabinets, see rack mount cabinets from this web site
The most common type of modern cabinet is known as the “EIA standard” or “19-inch rack mount cabinet”, where 19-inch refers to the approximate internal width of the cabinet, from mounting bracket to mounting bracket. For more information, see 19-inch rack. “Rack mount” computer equipment is standardized to this width, with mounting holes conforming to the mounting bracket standard. The computer height is measured in U`s, where 1U is 1.75 inches.