Hi @Mani,
Welcome to the Microsoft Q&A platform!
According to your description, to set up a high availability (HA) server for an existing Exchange 2016 environment, you need to follow these steps:
- Prepare the environment
- Install .NET Framework 4.5.2 or later and the Remote Server Administration Tools (RSAT-ADDS) feature.
- Extend the Active Directory schema and prepare the domain for Exchange 2016.
- Install Exchange 2016 on a new server
- Follow the installation steps to add the Mailbox server role on the new server12.
- Ensure proper configuration to match your existing server setup.
- Set up high availability
- This is the core component of high availability in Exchange. Create a DAG and add existing and new Exchange servers to it.
- Set properties such as DAG IP address, encryption, and compression as needed.
- Distribute mailbox databases among servers in the DAG to ensure redundancy.
- Verify the configuration
- Ensure that the DAG is functioning properly by testing failover scenarios.
- Use Exchange monitoring tools to keep an eye on the health and performance of the servers.
- Ensure that the new server is set up as an SMTP gateway (if necessary) and that it matches the configuration of the existing server.
For detailed steps and additional guidance, you can refer to https://learn.microsoft.com/en-us/exchange/high-availability/deploy-ha?view=exchserver-2019.
Please feel free to contact me for any updates. And if this helps, don't forget to mark it as an answer.
Best,
Jake Zhang