[Seattle-SAGE] Server room build questions

Gabriel Cain gabriel at dialupusa.net
Wed Apr 27 16:54:46 PDT 2005

Paul English wrote:
> I finally have a chance to set up a server room properly and I'd love to 
> get some tips and feedback on what, how and who. 

Sounds good.

> We are looking at signing a 5 year lease and as part of the lease having 
> the landlord build the server room space for us. I'm keen to be very 
> specific about what we want to ensure that we don't end up getting stuck. 
> We currently have 4.5 racks that we've built up over the last 3 years, and 
> I think we will be adding 1 more rack in the next 6 months. We are looking 
> at getting enough space for approx 20 racks which should be more than 
> enough.

Yeah, I would definitely make sure to spell out all the build-out details. 
Generally, if you leave room for corners to be cut, they shall be.  How 
savvy at building rack space is this landlord?  I'd be careful about making 
sure that they know what they're doing.

> We have machines in 3 categories:  


> So on to the questions:
> Given a commercial office space, does a roof-mounted AC make the most 
> sense?

Probably. ;)

> What are people's feelings on raised floors vs. tiles/anti-static carpet? 
> I'm very opposed to running network/kvm cables under floors (give me a 
> ladder rack any day), but raised floors can be handy for routing AC to the 
> front of the racks and running fat trip-causing power cables. 
> How much AC should I spec - get the maximum capacity 20 rack's worth now, 
> or get a lesser amount now and plan to upgrade? 

I would spec out all the capacity now.

> Should I spec out a backup AC? Or just plan on shutting down all of the 
> non-critical systems in the event of an AC failure. 

I would lean towards having additional capacity available / yes, do have 
backup HVAC.  I would very much hate to find myself in a situation where the 
AC wasn't available, and my customer facing machines were rebooting or going 
down due to the heat.

> How much power should I spec? On this one I'm fairly sure that I should 
> probably spec the full 20 rack's worth (200A?) and just get the breaker 
> panel put into the room with circuits sufficient for 6 racks. 

Only 200A for 20 racks?  I use 40+ amps in most of my racks (and all of them 
exceed 20A).   I'd go for 500A, at least.

> What are the considerations for a backup generator vs large (Liebert?) 
> UPS? I'm leaning towards an auto-start generator right now, with small 
> rack-mount UPSen on the 24/7 critical systems. 

UPS+Genset is generally the most reliable way of handling that, and you get 
power filtering to boot.  Beware those batteries in the UPSs.  A few months 
back, a colo providers I know of had a failure in their batteries (after 
being tested shortly beforehand, no less) that resulted in some downtime.

> Do we bother with a fancy dry fire supression system? Seems like a major 
> PITA and would take a big chunk out of the budget for everything else. 

Dry pipe solutions (i.e., smoke charges the pipes with water, heat releases 
the water) is found very frequently, and is in both of the facilities I've 
got gear in.

> Thanks in advance for the feedback. I think the answers will be useful 
> to everyone but if you feel like sending me your answer off-list I will 
> summarize the replies.

No problem Paul. :)

A lot of what you want to do depends on your budget.  Do you have a copy of 
_The Practice of System and Network Administration_?  If not, I'd buy one if 
I were you.  These topics are touched on in it, and it's a great book in any 


Gabriel Cain                                       www.dialupusa.net	
Senior Systems Administrator                   gabriel at dialupusa.net
Dialup USA, Inc.                                888-460-2286 ext 208
PGP fingerprint:   C0B4 C6BF 13F5 69D1 3E6B CD7C D4C8 2EA4 2B08 1C6D

The difference between a successful person and others is not a lack
of strength, not a lack of knowledge, but rather in a lack of will.

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