Managing DAG: Modifying a DAG Witness Server

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In the previous post we went over the process to configure a Witness Server and on this post we are planning to move the DAG Witness Server to a different server and you there are a couple of reasons  for an Exchange Admin to perform such task.

First, if the current Witness Server is being decommissioned and we need to bring a new one; the second good reason is that you are moving to a more robust solution, let’s say you started small with 2 DAG member in your main location and now you want to deploy a second Datacenter and use a third datacenter to host your DAG Witness Server to provide automatic failover.


For this post let’s say that we have a DAG with 4 members: 2 in Toronto (main site) and 2 in Porto Alegre (DR site) and we are going to move our current witness server to a third datacenter located in Paris (voilà I was able to fit my 3 favourites cities in a single scenario :) ).


Modifying the existent DAG…

We can chance the DAG Witness Server using either the EAC (Exchange Admin Center) or Exchange Management Shell, for this series the default tool will be EAC.

Let’s open the Exchange Admin Center, click on  servers, database availability groups, let’s select the desired DAG from the list (the current witness server is TOREX03). Then, click on the Edit (second button from the left).


In the general tab. Let’s type in the name of the new DAG Witness Server (in our scenario is PARFS01.apatricio.local) and then click on save.


Validating the changes…

There are a couple of ways to validate the changes that we have just performed, the simpler one is through EAC, back to the main page we should see the new witness server listed/


We can also go to the new DAG Witness Server and we should have a folder and a couple of file on it.


If we open the Failover Cluster we will noticed that the new information about the DAG Witness Server is also shown in the Quorum Configuration.


Removing the Share from the original server…

Now that we moved the Share to our new DAG Witness Server we can safely go to the original server and remove the share from it, after that we can also remove the content since they are no longer in use.

In order to remove the share, right-click on the Share and click on Properties, then click on Sharing tab, and finally hit Advanced Sharing… Uncheck the first option Share this folder and click OK twice.


At this point of the series we configured a DAG Witness Server and we know how to move around in case we need to.

Written by Anderson Patricio

Anderson Patricio

Anderson Patricio is a Canadian MVP in Cloud and Datacenter Management, and Office Server and Services, besides the Microsoft Award he also holds a Solutions Master (MCSM) in Exchange and several other certifications. Anderson has been contributing to the Microsoft Community with articles, tutorials, blog posts, twitter, forums and book reviews. He is a regular contributor here at,, and Anderson (Portuguese).

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