(Note: Please download the latest Installation Guide for Team Foundation and read the Upgrade sections for details on types of upgrades and steps to perform an upgrade to TFS 2010)
TFS 2010 provides a lot of flexibility in how you manage your collections. You can have multiple collections and easily move them from one SQL instance to another. One common scenario is to load balance your system by spreading your collections across multiple data tiers. You can do this before, during, or after upgrade to RTM. If you move a collection as part of your upgrade, you must run the RemapDBs command before the upgrade. The steps to follow are:
1. Backup DBs.
2. Uninstall TFS Beta 2 / Install TFS RTM
3. Move your collection database (backup/restore from SQL) to the new data tier
4. On TFS Application tier, run 'tfsconfig.exe remapdbs' and specify all your data tiers. For example:
tfsconfig remapdbs /sqlinstances:server1,server2\instancename /databasename:datatier1;Tfs_Configuration /analysisinstance:server3
5. Run the TFS Upgrade Wizard.
Note that if you move all your TFS databases to a new single data tier, you don't need to run RemapDBs. TFS is smart enough to figure it out. If you move one or a few database, you must run it. Just to be safe I recommend you run RemapDBs anytime you move a TFS database. There's no harm in running it.