Q: Building a small machine room? Materials/costs/etc.

Daniel Widyono widyono at cis.upenn.edu
Wed Sep 17 14:24:50 EDT 2003

Raised floor vs. overhead cable trays:

raised floor requires careful routing underneath -- you don't want to keep
lifting tiles and snaking things back and forth when changing cabling; also,
it can get cramped in there unless you're talking 6' raised floors (ahhhh, to
work for the government)

overhead cable trays are a pain to route as well, but end routing is much
easier to manipulate.

depending on AC with raised floor means you must keep the apertures to a
minimum (both size and number) else you lose cooling air flow everywhere 

raised floor? make sure you leave enough room between rack rows to be able to
pull at least two tiles in between (back to careful routing of cables)

dell's 42" racks fit nicely in 1x2 tile areas, fwiw.

torque on raised floor?  we use 4-post racks exclusively, no connecting to
the tiles/floor, just screw the extensions down to floor level

I'm not sure of the advantage of hidden wiring except if you're comparing
raised floor to running cables on the floor (the latter being a really bad
idea regardless of comparison).

BTW we always have at least two A/C's for each room, one semi-redundant.

Dan W.

> I didn't address the raised floor issue here or before, by the way, but
> yes there are some good things about a raised floor design.  For
> example, it is relatively easy to deliver AC and power directly to the
> racks from underneath.  On the other hand, the raised floor has to
> support the racks and they are (as noted) likely to be HEAVY and to
> TORQUE on their floor support as well as just press down on it.  Also,
> the hidden wiring is an advantage when it doesn't need to be worked on,
> then it becomes a small disadvantage relative to more open and
> accessible trays.  I suspect it costs more too.
> Somebody who has tried both kinds of floor and prefers raised may be
> able to do better than this.
>    rgb

-- Daniel Widyono                      http://www.cis.upenn.edu/~widyono
-- Liniac Project,     CIS Dept.,    SEAS,    University of Pennsylvania
-- Mail: CIS Dept, 302 Levine     3330 Walnut St  Philadelphia, PA 19104
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