RE: two databases in a server

This is one area that is just two broad to be able to say "Here is the right 
way to do it." There are just too many variables (as has already been noted). 
You also need to consider

   Different backup/recovery requirements
   Different support teams and how well they work together
   How well the apps handle resource (putting a low-business-impact, 
high-resource-hog app on the same server as a high-business-impact app is going 
to be problematic)
   Security issues
Everything is a tradeoff.

Regards,
Daniel Fink

Other related posts: