Would you use a database instance used for development work to store TFS Data Layer ? If that's not the case, what kind of separation would you use ?
Setup : we have ONE server for all common dev work. Due to physical constraints, we can't add anymore.
A new instance would be a good level of isolation. TFS installs a few databases, in addition to the sharepoint and reporting services databases. I just wouldn't be happy with all of those databases cluttering my primary instance, but that would work too.
