Exchange 2013: Setting up the Database Availability Group (DAG)

The DAG is also already included in the Exchange Server 2013 preview. I have tested the setup of the DAG, it is just as easy as with Exchange 2010.

I have installed a second Exchange Server for the DAG test (Described here). My test environment now looks like this:

I have configured the second network card as follows:

 

All protocols except "Internet Protocol TCP/IPv4" have been switched off, the cluster network is configured without gateway and DNS server. Server 1 is assigned 192.168.100.1 and server 2 is assigned 192.168.100.2 in the cluster network.

The DAG can now be created by logging into the ECP at "https://Servername/ECP". The "Database Availability Groups" tab can be found under the "Server" menu item. Click on the + sign to open the configuration dialog.

I select "DAG01" as the name and set my domain controller (RC01, see note at the end of the article) as the witness server. Click on "Save" to close the dialog. If everything went well, you should now be able to find an entry with the name "DAG01"

 

The creation of the cluster networks did not work automatically for me, so I configure it manually, for this purpose the checkbox "Configure Database Availability Group networks manually" must be set in the properties of the DAG (pencil icon)

In the menu "Database Availability Group" there are 2 gray items in the menu bar, with the second gray item the two Exchange 2013 servers can be added as members:

After clicking on "Save", the servers are added.

After the servers are added, they should also be displayed as members of DAG01

Since, as already mentioned, the automatic configuration of the networks did not work for me, I now configure the cluster network for replication manually by clicking on the first gray dot

A separate network for the replication of the DAG can now be set up here, for this I only define the name and add the subnet 192.168.100.0/24

Once the new network has been created, replication on the "MapiDagNetwork" can be deactivated by clicking on "Deactivate replication" under "MapiDagNetwork" in the ribbon on the right-hand side

The DAG and the members are now fully configured. Only the database copies are still missing. To do this, click on the small gray dot on the "Databases" tab

You can now add a server for the copy by clicking on "Browse"

After clicking on "Save", the database is copied to the server. Done!

Note:

In my test environment, I place the witness directory on a domain controller, which is not best practice and is not recommended for productive environments. During the creation of the DAG, a warning is generated indicating that the permissions on the witness directory are not sufficient. In order to create a valid witness directory, the computer account of the DC must be added to the Active Directory group "Exchange Trusted Subsystem". In addition, the "Exchange Trusted Subsystem" group must be added to the "Administrators" group. However, this should _ONLY_ in test environments.