We are running multiple (3 or 4) instances of SQL Server 2005 SP3 (EE) 64-Bit on one server. I would like to know if it is possible to upgrade one of these instances to SQL Server 2008 without affecting the other instances? Or, does all instances have to be upgraded at the same time? (Does the instances share some common files?)
If possible, what would be the best method to use to upgrade one instance?
Thanks in advance, Kevin