Exchange Upgrade Support

[Ashan_Dissanayake]

Dear Team,

Regarding the Exchange Server 2019 upgrade from 2016 versions, seeking confirmation on clarification on the best practices for migrating from 2016 to 2019 with the following setup.

• We have Exchange server 2016 DAG with 2 servers and it has been configured with the hybrid setup. 2000 mailboxes already migrated and around 1500 mailboxes are in On-prem. We would like to migrate our existing Exchange Server environment to 2019 and The goal is to continue using the exchange infrastructure for a couple more years.
• Also, we are planning to deploy a load balancer in the primary site.
• As per our BCDR planning, the new environment will include a third DAG server in the DR site, with a decision pending on whether to extend to a fourth node. The load balancer will be implemented at the primary site only, not the DR site.

[#2]

To upgrade to 2019, you basically install the new servers and a new DAG and then migrate the mailboxes from the Exchange 2016 servers to the 2019 servers. You will need to re-run the hybrid config wizard so it's reconfigured to use the new servers. The Exchange Deployment Assistant can help you with the process: https://learn.microsoft.com/en-us/exchange/exchange-deployment-assistant?view=exchserver-2019

[#3]

Dear Dan,
Thank you for your response.
Can you help with me for the below queries as well?
1. Do whitespace need to be removed from the 2016 environment before the migration?
2. When planning DB sizes in the Exchange 2019, do we need to include the current DB with whitespace sizes or exclude it?
3. Do the site resilience distribution model be Active/ Active or Active/ Passive?
4. Is it alright to plan the DR with 1 server? And how it will be supported when primary site goes down?
5. Initially, all 3 servers will be deployed in the same HCI cluster and will be moved to the DR site later, should it be alright, or any other concerns will be there when planning this?
10. Does whitespace occurs even when migrating mailboxes from one DB to another? And it will be the same case for migrating to cloud as well?

[#4]

You don't need to remove whitespace prior to migration. To size the target databases, you need to take into consideration the existing mailbox sizes, the user mail profile, and projected growth. generally I'd use active/active as I'm not a fan of having servers sitting around idol. You need to size DR so that there are enough resources to run all the mailboxes and client connectivity for the organisation

Use the Microsoft sizing calculator: https://techcommunity.microsoft.com/t5/exchange-team-blog/announcing-the-exchange-server-2019-sizing...