1.How to verify the overall health of the DAG?
Run the cmdlet of Test-ReplicationHealth
2.How to verify replication and replay activity?
Run the cmdlet of Get-MailboxDatabaseCopyStatus
3.How to verify that switchovers work as expected?
Run the cmdlet of Move-ActiveMailboxDatabase
4.What is Database Switchovers?
A database switchover is the process by which an individual active database is switched over to another database copy (a passive copy), and that database copy is made the new active database copy.
5.What is Server Switchovers?
A server switchover is the process by which all active databases on a DAG member are activated on one or more other DAG members.
6.What is Datacenter Switchovers?
In a site resilient configuration, automatic recovery in response to a site-level failure can occur within a DAG, allowing the messaging system to remain in a functional state. This configuration requires at least three locations, as it requires deploying DAG members in two locations and the DAG’s witness server in a third location.
7.When a Database failover occurs?
A database failover occurs when a database copy that was active is no longer able to remain active.
8.When a Server Failover occurs?
A server failover occurs when the DAG member is no longer able to service the MAPI network, or when the Cluster service on a DAG member is no longer able to contact the remaining DAG members.
9.What is Datacenter Failovers?
Since you can failover the namespace between datacenters, all that is needed to achieve a datacenter failover is a mechanism for failover of the Mailbox role across datacenters.