A systems administrator is designing a high-availability solution for the company's on-premises Exchange Server 2019 environment, which runs on Windows Server 2022 in two datacenters connected by high-speed links. Management requires that each mailbox database continue to mount automatically on another server if the active Mailbox server or its storage fails and that mailbox data replicate continuously so that no messages are lost. Which built-in Exchange feature should the administrator deploy to satisfy these requirements?
Database Availability Groups (DAGs) are Exchange's native high-availability mechanism. When several Mailbox servers are added to the same DAG, copies of each mailbox database are replicated between those servers. If the active copy becomes unavailable because of a server, storage, or network failure, the DAG's Active Manager automatically mounts another copy on a surviving server, providing database-level failover with minimal interruption to users.
The other options do not meet the requirement:
Network Load Balancing only distributes client traffic across servers; it does not replicate mailbox data or perform automatic database failover.
DFS Replication can synchronize file-system folders but it is not supported for replicating Exchange mailbox databases and cannot provide automatic database mounting.
NIC teaming aggregates or redundantly bonds network adapters; it protects a network path, not the mailbox database itself, and offers no data replication or failover for Exchange.
Therefore, deploying a Database Availability Group is the correct choice.