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what is actually meant by an 1u server? How can I check how many blade server does a chassis support?

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up vote 7 down vote accepted

A "U" is a Rack Unit, or 1.75 inches in height. A 1U server would occupy a single unit's space within a rack.

You would need to update your question to detail which chassis you're asking about. Different chassis can hold different numbers of blades, mezzanines, etc.

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+1, Additionally: Blade Servers go in a Blade Chassis, not in a Rack. The Blade Chassis mounts to the Rack. Rack Servers also go directly into a Rack. And different Blade Servers tank up different amounts in a Blade Chassis, some are half-height or full-height, some are single width or double width. And some Blade Servers have additional units next to them to expand their functionality. So, you'll have to provide a lot more info if you want a precise answer. – Chris S Dec 2 '10 at 21:52
or 4.5cm of course :) – Chopper3 Dec 2 '10 at 22:18

1u is a measurement of how much shelf space a server takes in a rack. 1u means one shelf space. Servers generally are 1u-4u but you can also get small 1/2u ones. Racks in a datacenter are commonly 48u.

How many blades fit in a chassis depends on the type of chassis. The specs from your manufacturer will show how many blade servers fit in their chassis. It's different for all manufacturers and models.

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I gleaned this from google:

1U Server= 1.75" of Vertical Rack Space 2U = 3.5" of Vertical Rack Space 4U = 7.00" of Vertical Rack Space

A full rack can contains 40 to 42U 1/4 Rack=10U (10 servers of 1U) Half rack =20 U (20 Servers of 1U)

Hope it helps

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48U is the most common "full" size in Enterprises, with 24 and 12 being half and quarter respectively. The smaller 40U units are more common in small/medium businesses where the rack cooling is attached on top of the rack. – Chris S Dec 2 '10 at 21:57
Cool. Thanks for the correction. – shagism Dec 2 '10 at 22:03

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