Lets create a New DAG.
To do this click “New Database Availability Group” in the Mailbox node in Organization Configuration in Exchange Management Console.
When create a DAG we should specify Witness Server which is used to establish a majority node set. Its recommended to use Hub Transport Server as a witness server. But if you decide to choose other server as a witness server you must add the “Exchange Trusted Subsystem” group to the local administrators group on that server. More witness server requirement refer this Technet article.
Specify DAG Name, Witness Server and the Witness Directory as shown in below figure.
Lets add Exchange servers to this Database Availability Group. To do this click “Manage Database Availability Group Membership…”.
Add Exchange Servers.
if you do not have DHCP available on your network while the member servers are being added to the DAG, you will get the warning saying that “The network name “DAG01″ is not online. Please check that the IP address configuration of the Database Availability Group is correct.”“. So if you do not have DHCP enabled in your network, you can manually assign IPs for the DAG. To do this go to properties of the DAG01 and click “IP Addresses” and add IP addresses for the group.
If your DAG Group contains exchange servers which are in different networks (Subnets) you should add all IP addresses to this list. See the “DAG Name and IP Address Requirements” section in this TechNet article.
Now I am renaming my DAG networks as MAPI and REPLICATION for easy understand. Also we can Enable/Disable Replication on each networks.
To get Database Availability Group details through Exchange Management Shell run below command.
Get-DatabaseAvailabilityGroup | FL
Lets see the status of “cluster core resources“. Open “Failover Cluster Manager“
Check the status of Cluster Core Resources
Let’s add database copies for each mailbox servers. Also note that all copies of a database must use the same path on each server containing a copy.
Select other Mailbox Server name and click Add.
Do the same steps for all Mailbox Databases. Now you can see the copy status of Mailbox Database.
Now I am disconnect the EX2 Exchange server from the network. Now you can see DB02 database is mounted to EX1 exchange server.