Exchange Cross Site Disaster Recovery

Question

Problem description: In the Exchange 2019 DAG cross site disaster recovery architecture, under what circumstances will the primary node database be switched to a replica node of another node? Please also provide the explanation address on the official website. Thank you!

Answer 1

Hi @军 陆 ,

under what circumstances will the primary node database be switched to a replica node of another node?

By “switch”, are you intended to say "failover" which occurs automatically due to some unexpected events like power failure? If this is true, by default, a database can failover to any of the available DAG members automatically, including the DR site.

For more details about the process of database failover, you can refer to the official document below:
Switchovers and failovers

If you have the interest to learn more about how the Best Copy Selection process works, you can check the following article:
Exchange Server Active Manager

Additionally, if you are concerned about the automatic failover to the DR site and would like to prevent this from occurring, here's a blog about this topic for your reference:
Using Activation Policies to Prevent Database Copies Mounting in Other Sites

(Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.)

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