Hi all, We would like to setup a few DAG's and have read Enterprise Windows 2008 or R2 is required., can someone confirm ? In addition, CAS and HUB requires Windows 2008 Std. TIA

Confirmed. DAG will require the Enterprise Edition of the OS, either 2008 or 2008 R2. This is due to the requirement of the Windows Failover Cluster service. You are right about the CAS/HUB, those can be Standard Edition of Windows. If you need Windows Network Load Balancing for CAS, this is included in the Standard Ed of OS. Tim Harrington - Catapult Systems - http://HowDoUC.blogspot.com

Thank you Tim. "TWHarrington" wrote in message news:ca12433f-7764-4b27-8167-ac18b2013c9d... Confirmed. DAG will require the Enterprise Edition of the OS, either 2008 or 2008 R2. This is due to the requirement of the Windows Failover Cluster service. You are right about the CAS/HUB, those can be Standard Edition of Windows. If you need Windows Network Load Balancing for CAS, this is included in the Standard Ed of OS. Tim Harrington - Catapult Systems - http://HowDoUC.blogspot.com

Documented here: http://technet.microsoft.com/en-us/library/bb691354.aspx Exchange 2010 Prerequisites If you're installing the Mailbox server role and you intend the server to be a member of a database availability group (DAG), you must be running the Enterprise Edition of Windows Server 2008 or Windows Server 2008 R2. The Standard Edition doesn't support the features needed for DAGs. You can't upgrade Windows when Exchange is installed on the server. and http://technet.microsoft.com/en-us/library/aa996719.aspx http://www.microsoft.com/exchange/2010/en/us/system-requirements.aspx