My Company is currently in the early planning phases of a project where we are playing with the idea of hosting our web project on multiple continents. The idea is to push local users to the closest server possible to decrease loading times. This will likely involve mirroring the web project across each server. Thats cool and not our dilemma at the moment - remember we are in the planning/design phase.
The concern which was brought up yesterday (and caused myself and acouple others to lose sleep) is the SEO effect of hosting on multiple servers. What our fear is, is that with say 3 servers running in 3 different continents we are going to have duplicate content on each of those 3 servers. Now we can use url canonicalization to go from domain.com www.domain.com so search engines view the url as a single url and everything resolves to the same url (good for SEO). But what we wont be able to do that any of us can foresee is IP canonicalization to tell search engines that all three instances are all the same site possibly confusing SEs on which url is the correct one to index (or so our worry is). In the experience of other webmasters is there a correct way to go about this? Has in any of your past experiences has running multiple instances of a website in this manner negatively effected your SEO efforts? If yes do you guys have any ideas on how to minimize the potential of pages not being indexed by going this route?
I know its a pretty small part of the ranking algorithms but it is enough that we want to have this planned out as best as we can especially considering the scale of the project.