Just a couple of observations based on experience: - You'll most likely run out of power well before you run out of physical rack space. - You'll (hopefully)

Just a couple of observations based on experience: - You'll most likely run out of power well before you run out of physical rack space. - You'll (hopefully) spend less time in the data centre than you think, especially if you have good lights out access, remote power bar access etc. If you're locating in a large city you can often get a better deal somewhere in the suburbs rather than downtown with very little downside (at least that seems to be the case here in London). - Interconnects between racks can be awkward to get set up, and you can't necessarily get the rack next door when you want more space. - Redundant everything will save you a lot of hassle, but gets quite expensive. In particular redundant power will save you from downtime when the data centre decide they need to take one of the power feeds down for maintenance (it happens), and setting up redundant (external) networking has the same effect. Having a second network for admin access prevents you from being locked out in some failure cases. Hot swappable drives are useful for systems which are awkward to take offline (e.g. database servers), but not massively useful elsewhere if you have good redundancy at the server level. - Data centre rack floors are about the most unpleasant place to work you can imagine :-) - If you can get a handle for how competent the data centre are at mitigating DoS attacks it's a useful datapoint. If they aren't on the ball an attack against anyone hosted in the same place will take you offline too. having said that, I'm not entirely sure there's a fool-proof way to determine this ahead of time. - You can generally borrow a cart with a keyboard and monitor on it to wheel up to your rack, so no need to have those permanently installed. - Keep a stash of network cables, cable ties etc. at the bottom of your rack - it's annoying to show up only to find you've forgotten that kind of thing. - You may need to register authorised employees before showing up, so make sure you do that before taking your new intern to help rack a server. Expect them to ask for ID before letting you in. - Data centres (at least some of them) will take deliveries on your behalf, so there's normally no need to get things shipped to your office then drive them out yourself.