Server Racks 101

Monday morning brings us all, coffee fueled, to the table in Rack Solutions.  We have come to the conclusion, that there are a lot of unanswered questions in the minds of our current and prospective clients and customers.  We are always here to help.  So we are putting together a small, but informative series on how to pick your server rack.

Lesson 1:


How much rack you need is the first question you should ask yourself.  Do you want to go to the ceiling? Do you want to have extra room in the front or back?  Assess your space.  Will you have techs in the room with the servers at all times? Will you need to make room for desk space? Will you be using a rack seat, kvm setup and not need the spare desk or rolling chair?  There are a thousand questions that come to mind when looking for size qualities in a server rack.

What is an RU?

A rack unit or RU (sometimes referred to as U) is a size dimension that describes the height of the space given for the equipment you are mounting in your server rack.  This height is a standard set by the Electronic Industries Alliance which stands for 1.75 inches or 44.45mm.

We shy away from saying things like standard because so many people customize their racks to fit their needs; however an RU continues to stay an RU so is actually a standard unit of measurement.  Height of a server rack is measured, predominantly, in RU’s.  This way you can tell at a glance how many pieces of equipment you can store in one rack.  42U is a very popular size.  This holds just over 6 feet of equipment.  Most server chassis are sold by the RU.  Be it 1U or 1.75 inches or 3U of 5.25 inches, you can judge how many of those chassis you can fit into a single server rack rather easily.

Is extra space necessary?

It really depends on what you are going to do with the server rack. If you are selling space, in a colocation rack situation, extra space may not be available.  However, there are lots of uses for extra space on a rack.  Some people like to use that extra RU space for a shelf or storage area.  You can even get a locked box to put extra items into, as well.  You can use an extra U space for a seat as well, like the rack seat.  It’s like having a built in chair for every server rack. Your techs will thank you.   As far as being absolutely necessary, no an extra space is not necessary.  It is also recommended, especially for air flow management, that you cover the extra space with a filler panel.  This will help to control airflow in the server rack itself.

Next up – How to measure a server rack…


Server Racks 101 - RackSolutions
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Server Racks 101 - RackSolutions
In this new series, RackSolutions provides helpful tips for buying a server rack. The first tip is about finding the right size, and how to factor in extra space.
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