If you are planning to deploy Exchange Server 2010 Database Availability Groups, and you virtualize your Exchange environment, then it is important to understand the supported scenarios.

Microsoft makes it very clear in their system requirements for Exchange Server 2010:

Microsoft doesn’t support combining Exchange high availability solutions (database availability groups (DAGs)) with hypervisor-based clustering, high availability, or migration solutions that will move or automatically failover mailbox servers that are members of a DAG between clustered root servers. DAGs are supported in hardware virtualization environments provided that the virtualization environment doesn’t employ clustered root servers, or the clustered root servers have been configured to never failover or automatically move mailbox servers that are members of a DAG to another root server.

In short, DAG members should have any virtualization high availability options disabled.

This is in slight contrast to the advice from VMware themselves:

While the use of database availability groups on top of hypervisor based clustering is not a formerly (sic) supported configuration, internal VMware tests have shown that the two technologies can co-exist and can be a viable solution to ensure maximum recoverability in the case of a host failure.

To paraphrase, it isn’t supported but we think you’ll be fine.

You might get some push back from customers or managers who have been sold on the idea of VMware HA for everything, or who take the line from VMware as implied support for the configuration.  But in the real world I prefer to go with what is supported over what is possible.

About the Author

Paul Cunningham

Paul is a former Microsoft MVP for Office Apps and Services. He works as a consultant, writer, and trainer specializing in Office 365 and Exchange Server. Paul no longer writes for Practical365.com.


  1. James B

    This is an old article, but timely. I currently have an Exchange 2010 server on a stand-alone 2012 R2 server. It’s configured as two servers, one with mailbox, the other with the CAS, HUB, etc roles. I’m concerned the old server will run out of space, so I’ve configured a second server and planned a live migration of my Exchange group over a weekend while traffic is low. I’ve successfully performed live migrations of other servers, but have not tried Exchange. Sounds like it’s supported by Microsoft. Has anyone successfully done this without shutting down the VMs first? They are both identical servers and the virtual switch names are the same on each box.

  2. Zay

    @Intisar, when you say clustering, please elaborate. In Exchange 2010, clustering is automatically activated/implemented when a DAG is setup. Are you referring to clustering as to how it was implemented back in the days of Exch 2003?

  3. intisar Albarwani

    Hello their ,,, I know you r all professionals and all and my question may sound abit stupid
    but i really need to know how to preform clustering in exchange 2010??

  4. Magno Alberto

    With the availability of SP1, you can use DAG with Live Migration and VMware HA… well… as it is written in the documentation, but will it work in real scenario?

    With Exchange 2010 SP1 (or later) deployed:
    Exchange server virtual machines (including Exchange Mailbox virtual machines that are part of a DAG), may be combined with host-based failover clustering and migration technology, as long as the virtual machines are configured such that they will not save and restore state on disk when moved, or taken offline. All failover activity must result in a cold boot when the virtual machine is activated on the target node. All planned migration must either result in shutdown and cold boot, or an online migration that makes use of a technology like Hyper-V Live Migration. Hypervisor migration of virtual machines is supported by the hypervisor vendor; therefore, you must ensure that your hypervisor vendor has tested and supports migration of Exchange virtual machines. Microsoft supports Hyper-V Live Migration of these virtual machines.

  5. Dinesh Silva

    “In the real world I prefer to go with what is supported over what is possible” ( 200% correct, specially with Microsoft :D).


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