Database Availability Group DAG Articles
Step 04 : Creating the Exchange DAG
Now it’s a time to create DAG [ Database Availability Group ]
From the ECP, go to servers > availability groups of database > this page appears the list of available DAGs > Press +to add a DAG.
Step 05 : Add Exchange Servers to DAG
DAG is created and ready to add servers
During this process : , the Failover Clustering feature is installed on each server and a cluster is created.
so this process could take longer time > keep calm 🙂
Step 06 : Configuring Network Management
this part [ configure network Management] is optional since it’s already have been done with cluster configuration
Step 07 : make copy of Database in DAG
as we see below currently only we have one copy of each Mailbox Database , which does NOT provide redundancy
so the last step after configuring DAG successfully is just to make copy of Mailbox database in another server
Conclusion
A database availability group (DAG) is a high availability (HA) and data recovery feature of Exchange Server 2016.
(DAG) is the base component of the Mailbox server high availability HA
DAG concern to have two copies of same Exchange Mailbox Database , in two different Servers >
So if one Exchange Server Accidentally Offline > then the other server leep serving client users through second replica of Mailbox Database
