How Many Rack Units Are Needed?
 

I am looking at building another computer. This one is more for servering then the busted up Compaq that I am currently using. I was wondering how many rack units I should look at in a case. Is 2 enough?

For a custom built rackmount case 2U is what I would go with, it will provide you the flexibility of using most components while still keeping your cost down per U if you are looking to colocate. Only things you will need to watch out for is cooling components, you most likely will not be able to attach a standard CPU heatsink/fan. A 4U case of course allows for much more room and the flexibility to use whatever hardware/cooling you want but if your going to colocate something that large the cost per U is pretty high.

What kind of cooling would work with a 2U? I have plans to colocate eventually.

I am not sure about 2u but 1u server fans are so loud you cant hear your self think. If you don't plan to co-locate right away you may want to consider building a regular tower server. When I built my 1u server it was so loud that you could hear it outside of my apartment.

As far as cooling the good 2u server cases already come with all the cooling fans you will need. (except the processor fan) Check out Newegg they have plenty of 2u cases to choose from.

I am running out of space for tower computers. I am actually looking at picking up two or three more computers. With the ones I already have, I definitely won't have space.