Upgrading Exchange Server 2010 RTM to SP1 is a relatively straightforward process. However, DAG member 's upgrade is not easy , this document intro how to upgrading RTM to SP1 in DAG environment step by step process . For you reference. ;)
Enjoy!
Justin Gao
Microsoft (China)
Using MDOP 2010 refresh version application virtualization v4.6 to deployment Office 2010 professional plus x64 to Windows 7 client .