Using an Azure VM as a DAG Witness Server

Published Jan 09 2015 06:00 AM 35.1K Views

Update 8/13/15: Since publication of this blog post, there have been change in our Azure support statement related to Exchange Server. Please see KB 2721672 for more information.

I’m happy to announce support for use of an Azure virtual machine as an Exchange 2013 Database Availability Group witness server. Automatic datacenter failover in Exchange 2013 requires three physical sites, but many of our customers with stretched DAGs only have two physical sites deployed today. By enabling the use of Azure as a third physical site, this provides many of our customers with a cost-effective method for improving the overall availability and resiliency of their Exchange deployment.

You can learn more about the deployment and configuration process, as well as learn about our best practices in the TechNet Library article.

It’s important to remember that deployment of production Exchange servers is still unsupported on Azure virtual machines, so it’s not yet possible to stretch a DAG into Azure. This announcement is limited to deployment of a file share witness in the Azure cloud. Also note that this is not related to the “Cloud Witness” feature in the Windows Server Technical Preview. Stay tuned for future announcements about additional support for Azure deployment scenarios.

Jeff Mealiffe
Principal PM Manager
Office 365 Customer Experience

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Great news!. I was just discussing the applicability of doing that with one of our customers :)
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@Nate: The witness server must be in the same Active Directory forest as the DAG. As per

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Good to have such kind of feature. You will be spending at minimum US$1,000+ per year for one server just on pure Azure. Azure express route is all together different investment as you would want to have secure connection between Azure and On-Premises.


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Does the Azure witness server need to be a member of the same domain the Exchange servers are in? Or can we build a new domain in Azure and establish a one-way trust back to the domain Exchange is in?
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