Rack Unit Measuring Tape

By stretch | Monday, July 9, 2012 at 1:45 a.m. UTC

The other day I was taking inventory of servers in a data center, and the idea popped into my head for a measuring tape denoted in rack units. This would save a good deal of time when determining the position of a device in an equipment rack, or the amount of free space available. Of course, like nearly every idea I've had, I was not the first. I found a product called Rack Ruler on Amazon for $23.97:

rack_ruler.jpg

rack_ruler2.jpg

Neat, but $24 is a tad expensive for an obscure tool of undetermined quality. Knowing that a rack unit is exactly 1.75", one could easily repurpose a regular SAE measuring tape by marking it at the appropriate intervals.

About the Author

Jeremy Stretch is a network engineer living in the Raleigh-Durham, North Carolina area. He is known for his blog and cheat sheets here at Packet Life. You can reach him by email or follow him on Twitter.

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Comments


Mike Donovan (guest)
July 9, 2012 at 1:10 p.m. UTC

I got one of these as a promotional item years ago, but someone borrowed it. :-(

I'd love to see someone sell rolls of masking tape with marks at 1.75" intervals.


A guest
July 9, 2012 at 5:17 p.m. UTC

At my old job all the headends had several rack high peaces of wood which were marked out with the RU messurments. these came in very handy as I was docuemting equipment additions. they just would not be easy to transport from location to location like the tape.


Mark (guest)
July 9, 2012 at 11:10 p.m. UTC

I had one of these, got for a bit cheaper than the amazon price from an outfit which specializes in A/V equipment. I carried this around in my bag for years and on the occasion or three that I needed it, it more than paid for itself.

I feel like some platform chassis used to come with a cardboard RU planning template that was a bit to bulky to carry around but tempting to keep stashed in the DC somewhere for future use.


brendan
July 11, 2012 at 12:32 a.m. UTC

I like how the Dell racks have the numbers in the front and back. Is this not a standard now?


Justin (guest)
July 13, 2012 at 4:44 a.m. UTC

They sell a magnetic tape that you stick next to the holes and has the measurements.


root_taker (guest)
July 14, 2012 at 1:51 a.m. UTC

How about the cheaper two post racks where the holes are all spaced differently? I would soon get me something to measure with if I had to deal with them things again on a regular basis...


ddunkin
July 31, 2012 at 7:00 p.m. UTC

Once you learn the hole spacing (at least on our Chatsworth racks), you can eyeball it easily enough. A single U is 3 holes spread apart, adjacent units are identified by the pairs of holes close to each other. I don't have to think too hard about it.

I also use multi-colored electrical tape to mark a specific range of space on the cable management side (aligned to the rack units), then throw a label in the middle.


DKaine (guest)
October 7, 2012 at 5:50 a.m. UTC

I'm pretty sure brick masons rulers/tape measures have markings at 1.75", in addition to their other markings. They're mass produced, and you can probably get them for much cheaper than this tape.


ct_cmptr_guy (guest)
October 9, 2012 at 3:06 p.m. UTC

Late reply but I have taken to using a Sharpie marker to number any cabinets that don't come pre-numbered (Dell and APC are in my experience). If the rails are black powder coated, I would try out one of the silver Sharpies.


Colin D. Hardy (guest)
January 7, 2014 at 4:41 p.m. UTC

We found the standard tape measure with rack units very awkward...so we have come up with a magnetic tape, that looks much like a tailors tape measure,but it can be placed on a rack or cabinet, while one racks equipment according to a drawing or it can be used to audit existing facilities...

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