Preparing an Exchange Server 2010 SP1 DAG Member for Updates
For Exchange 2010 with Service Pack 1 the process is a little easier thanks to some scripts provided by Microsoft. Open the Exchange Management Shell and navigate to the scripts folder on the Exchange server.
cd $exscripts
Next run the StartDagServerMaintenance.ps1 PowerShell script.
.\StartDagServerMaintenance.ps1 -serverName ho-ex2010-mb1
The script will automatically do the following tasks for you:
Calls Suspend-MailboxDatabaseCopy on the database copies.
Pauses the node in Failover Clustering so that it can not become the Primary Active Manager.
Suspends database activation on each mailbox database.
Sets the DatabaseCopyAutoActivationPolicy to Blocked on the server.
Moves databases and cluster group off of the designated server.