As mentioned in the blog, "So many factors to consider!" Do your homework early and upfront even if planning to colo just an Atom or Soekris box. I can tell you that moving many multiples of racked equipment via semi-truck from one datacenter to another is not an enjoyable experience.

Ping - Power - Pipe : Ask everything you need. If a datacenter is unwilling to share or discuss who they are, what they do and what they offer then walk away. Colocation is a buyer beware environment.

Here's a VERY ROUGH list/braindump of questions that AT THE VERY LEAST you need to know before placing equipment with the colocation provider/datacenter.

Tier I,II,III, IV datacenter? Who owns the datacenter? Investors? What's your ASN number(s)? Carrier neutral facility? How many connectivity providers are present in the data center? Does data center run BGP over these providers? IP Transit providers - Bandwidth Pricing? Overage pricing? Straight $mbps/month? Who manages your network? Ip allotment? Assignment procedure? High density for micro vms(Heroku style)? 200 VMs per host meaning 200IPs per vm. Swip/rwhois updates on assignments? Cross-connects? Cross connect pricing? Charges? Local loop(last mile connectivity) charges? BGP support? Is our traffic on a private/separate v-lan from your other customers?

Infrastructure? -Redundancy in detail -Brands -Networking -Connection -Power. Maintenance programs?

A/B feeds from two separator breakers or breaker panels or better yet two Utility Power Service Provider if they are truly A/B feeds. A/B Diesel-Generators? Additional fuel storage on site? Is a PDU included? If so, how many outlets and is it accessible from the web or telnet? What type of hand off/drops to your rack will you be provided (Ethernet)? Are there raised floors? Are there any fire suppression systems in place? Physical/Video Security? Biometrics? Screening of employees?

Insurance requirements to colocate equipment with you?

On-site visit requirements? 24x7 staffing? Remote Hands - Cost and Abilities? What's included? Shipping/Receiving of hardware?

Sas II 70 or SSAE 16 certification? Audit available for review? -Common practices -Staffing -Security -Emergencies - Escalations -Contacts Outage alerts? Notifications through Twitter or similar offsite status page? RFOs for past outages? What's been your corrective action?

Power density per rack? 80% rule or true metered? Can you rack the equipment for us? Who provides cabling? Types of rails for servers? Billing-95th or other? Rack size? Partitioning available? 4u/10u/Quarter/Half? Cages? Lockable or baker's racks? Shared with others?

Finally, ask for a listing of ALL fees.