Geo Disater Recovery and Geo Replication

@Kumar, Ritesh Thanks for reaching out. In a scenario where the primary namespace of an Azure Service Bus with Geo-Disaster or Geo-Replication enabled goes down and cannot receive messages, failover to the secondary namespace is the recommended approach to ensure message delivery. However, as you mentioned, there may be a brief period of time during the failover process where messages from publishers are rejected.To handle this scenario, you can implement a retry mechanism in your publisher application. If a message fails to be published due to a service disruption, the publisher can attempt to resend the message after a delay.

In addition to implementing a retry mechanism, you can also consider using a dead-letter queue to capture messages that are not delivered due to the primary namespace being down. The dead-letter queue can be configured to automatically forward messages to the secondary namespace once it becomes available, ensuring that no messages are lost.

do let me know incase of further queries, I would be happy to assist you.