Rack U's in General

[Jim_366]

Trying to find out if there is an industry standard for where a U number is started at the bottom of a rack? Do they call the bottom spsce 0 or 1?

[kcpant · Accepted solution]

Hi Jim,

AFAIK, the starting point of rack cabinet is marked as 0U, and then measured 1,2 and so on , in all directions ( dimensions).

[Jim_366]

Thanks...just to clarify the starting U space is labeled as 0.

[timmy b.]

Jim,
Just a couple of things for you.

A "U" is 1.75 inches.

Not all cabinets count from the bottom to the top, some have top down numbering.

I hope this helps.

Good Luck - Tim

[Jim_366]

Thanks...Are all HP racks labeled the same? Starting with 0 as the first U.

[timmy b.]

Jim
HP racks (when labeled) will always start with 1U at the bottom.

When you hear the term 0U it will usually mean a space that is out of the normal "equipment" rack space, meaning cable management or ventilation areas.

More tidbits:
The older style of HP racks have sheet steel sides, are "quartz" in color, and are called Rosebowl or Rosebowl 1.

The newer style is called Rosebowl II, is also quartz but can also be graphite in color, and has removeable plastic side panels of either 8U or 9U size. (9U is located ONLY at the bottom of the rack, all others are 8U) http://www.hp.com/racksolutions

The newest racks are the 10000 series, along with it's predecessor on the Compaq side, the 9000. http://h18004.www1.hp.com/products/servers/proliantstorage/racks/10000series/benefits.html#quality

I hope this helps.

Good Luck - Tim