How Would You Build a Datacenter?

InOverOurHeads asks: "Some of my coworkers and I are building a new datacenter for our company. We're a growing startup, we have about 50 servers now and expect to have about twice that before too long so building to grow is key. Now that we're about $15,000 in to the project, it is looking and feeling more and more like we were way over our heads. We have 4 racks wired to a single 20amp circuit. Our UPS is at 90% load and we only have 10 machines on it. We have all of our cooling on one side of the server room where it is about 60 degrees, the other side of the room where the servers exhaust is about 30 degrees warmer, so it appears that we have some convection problems with only a handful of the machines on, right now. We're realizing that there is a lot more to building a datacenter than racking servers, what else have we missed?"

"On the positive note, we have a really nice overhead wire rack, that's looking good and all of our wiring is really tight looking; all the colors match, all the cables are labeled, they are all the right length, etc.

Are there any guides or how-tos on this? Since we're going to bite the bullet and tell the boss that we messed up we want to try to correctly measure the rest of the work involved in making it work. What happens when the UPS is at 100% load and how Dell servers react to being under powered?"