I'm in a new environment that has a 3-server DAG on Exchange 2010 SP2, with one of those DAG members in a different AD site. I wanted to update the DAG member in the separate site to SP3 first. Being new to DAGs, I didn't realize that I couldn't update the schema directly on the 3rd DAG member because it wasn't in the same AD site as the Schema Master. Making it more tricky, the Schema Master is running Server 2008 Core, so when I try updating the schema directly on it, I get "Exchange Server 2010 requires .NET Framework 3.5". Both of the DCs in the AD Site where the Schema Master is are running Server Core.
How do I go about updating the schema for Ex2010 SP3 when the Schema Master is running Server Core?