Moved from http://blogs.msdn.com/vijgang
SharePoint 2010 User Profile Synchronization has undergone a major architectural change. I have attached few articles below which explain this in more details. Now back to upgrade considerations, one of the major concept is the introduction of the “User Profile Service Application” and “User Profile Synchronization Service”.
So to understand this better, let’s consider this scenario:
We have a Single Server SharePoint deployment with the following MOSS 2007 configuration,
Now how does this change in SharePoint 2010? So to check this, I did an in-place upgrade to SharePoint 2010 which succeeded without errors.
So this is where you get an option to choose from either of the “Service Application” to be associated with this “lone” synchronization service. What this means is that at this point in time if we proceed to select one of the Service Application (from the screen shot above), then only that User Profile Synchronization will function, the other “User Profile Service Application” cannot be synchronized.
The solution to this lies in partitioning the “lone” chosen “User Profile Service Application”. How do we do that? Well that’s another blog, I am still working on it!
Refer: Configure profile synchronization (SharePoint Server 2010) http://blogs.msdn.com/spses/archive/2010/04/01/sharepoint-2010-provisioning-user-profile-synchronization.aspx