I have a customer that wants to bring up a secondary DC for redundancy and they are using SBS2008. I don't see a problem with this. It is just a matter of updating the schema with Forest prep and AD prep using windows 2008R2 disk in the SBS2008.
The question I have is this Company has a SQL Database product. Is the Schema upgrade going to mess with the SQL server.
I have made a backup of the system state using wbadmin startsystemstateback.
Am I missing anything?