[NTLUG:Discuss] When do you save with rackmounts?

[Terry Hancock]

Hi,
Following the "2U" system thread, it's obvious that some of you use rackmount 
systems.  I'm wondering what the tradeoffs are.

Obviously rackmount systems tend to be expensive for the same level of 
system, and they save space.  But unless you really are in a business where 
the physical computer cases actually take up a large fraction of your floor 
space, it's hard to believe that this alone is worth the extra cost.

For comparison, I have been considering setting up a "poor man's rack" by 
using 16" steel utility cases and installing surplus mini-tower form factor 
computers (running headless, of course).  The shelves are about $10 to $20, 
and the computers, which tend to be a little behind the times (say 500 MHz 
instead of 1500 MHz, etc), typically only cost about $150.  I should be able 
to fit a good 20 systems on one shelf set, which seems pretty dense to me 
(maybe 4X bulkier than a true rackmounted system).

What other factors should be considered?  Does a rack save you in other areas 
(maintenance, perhaps)?  Has anybody listening done both so that they can 
compare directly?  I'm not trying to trash rackmounting or anything -- quite 
the contrary, I think they're pretty neat, but I'm wondering what you have to 
be doing to make them genuinely practical.

I've considered such a setup for a distributed web server solution and also 
for setting up a Beowulf compute server, but I've not gotten so far as 
writing specs or anything.  Any thoughts?

Cheers,
Terry

--
Terry Hancock ( hancock at anansispaceworks.com )
Anansi Spaceworks  http://www.anansispaceworks.com