Exchange 2016 DAG Configuration

In this post I’m going to show you the process of creating an Exchange 2016 DAG. The DAG will consist of 2 member servers and one file share witness. And as with previous Exchange versions, there are a few requirements to follow to successfully create a DAG.

To start, the .edb file and log locations will need to be consistent across all the servers that will be a member of the DAG. It’s good practice to separate out the logs and the databases to their own drives. In my case, I have placed the database files on the E: drive and the log files on the L: drive. To verify the location of these files we can run a quick PowerShell command from the EMS.

[PS] C:\Windows\system32>Get-MailboxDatabase |FL Name,EdbFilePath,LogFolderPath
We also need to ensure that the Exchange Trusted Subsystem group is a member of the local administrators group on the server we are going to use for the witness.
With those two requirements verified, we are now ready to create the DAG. In this case I am using the Exchange admin center to create the DAG. To begin, navigate to servers and select database availability groups. Select the + to create the new DAG. Enter the name you wish to use for the DAG, the server that will be used as the witness server, and the directory used for the witness. You also have the option to enter an IP address. Since I am running Windows Server 2012 R2 and will be creating an IP-less DAG, I have left the IP address field blank.

Once the DAG has been successfully created, we need to add our servers to the DAG. Choose the Manage DAG Membership icon and add the desired servers to the DAG. The process will install Windows Failover Clustering on the selected servers.

Once the process completes, you can see that the servers are now listed as member servers of the DAG.

Now that the DAG has been created, the only thing that is left is to create database copies across the member servers. This process can be done through the EAC. Navigate to servers, select databases, and choose the database you want to replicate. Select the more option, and then Add database copy.

Browse for the database server you want to replicate to and select the appropriate activation preference and choose save.
The Exchange database will begin seeding data to the second DAG server. You will be provided a status of the seeding process.
 Once the seeding is complete, you can use the following command to look up the replication status of the database.
[PS] Get-MailboxDatabaseCopyStatus -Identity MDB16-2