We have a 2003 Small Business Server Premium with Exchange and ISA installed and working. We have 55 users, our Exchange Store has grown to 65GB and both users and Exchange data are going to increase. We have to move to an Exchange version that can go beyond the 75GB limit and we may exceed to 75 user limit. We also have a 2003 Server that is a global catalog that we use as a Terminal Server.
My thinking is that we should add a 2008 Server with Exchange 2007 and migrate users to the Exchange 2007 Server to resolve the Store size limit. Is that the best option and should the new server be a domain controller and should I remove Exchange 2003 from the SBS server once the mailboxes and all other information is migrated over?
I also think that we will soon exceed the 75 user limit in SBS and I want to make sure what I do now will help what I need to do later to remove SBS from the domain. What is the best migration solution to help our network in the long term? We only plan on adding one Server to the network although it can be a large one.