Microsoft recently announced the public preview of its new Geo-Replication feature in the Azure Service Bus premium tier. This feature allows continuous replication of a namespace's metadata and data from a primary region to a secondary region, which users can promote at any time.
Azure Service Bus is Microsoft’s fully managed messaging service, enabling reliable and secure communication between distributed applications and services across cloud and on-premises environments. The new Geo-Replication feature for this service is designed to provide robust protection for Azure Service Bus applications against outages and disasters, complementing existing options such as Geo-Disaster Recovery and Availability Zones.
Unlike the existing Geo-Disaster Recovery feature, Geo-Replication replicates metadata and data. It can establish resilience between Azure regions, such as the East and West US. In addition, Availability Zones provide resilience within a specific geographic region.
Eldert Grootenboer, a senior program manager on the service bus team at Microsoft, writes:
The Geo-Replication feature implements metadata and data replication in a primary-secondary replication model. It works with a single namespace, and at a given time, there’s only one primary region serving producers and consumers. A single hostname connects to the namespace, which always points to the current primary region. After promoting a secondary region, the hostname points to the new primary region, and the old primary region is demoted to the secondary region. After the new secondary has been re-initialized, it is possible to promote this region again to primary at any moment.
Service Bus Premium Geo-replication (Source: Tech community blog post)
Microsoft's competitors offer similar messaging services with disaster recovery features. AWS Simple Queue Service (SQS) ensures high availability and fault tolerance by distributing messages across multiple availability zones within a region. This means that messages remain accessible and are not lost even if there is an outage or disaster affecting a specific data center. Similarly, Google Cloud Pub/Sub provides high availability and disaster recovery by automatically replicating data across multiple regions, ensuring that messages are reliably delivered and available even if one region experiences an outage or disaster.
Clemens Vasters, a Principal Architect for Messaging and Real-Time Analytics at Microsoft, tweeted a bold statement:
#Azure Service Bus is the most powerful transactional hyperscale queue broker in existence.
Introducing multi-region, synchronous (RPO-Zero), or asynchronous namespace replication (all messages and message states!) as insurance against region failures.
Lastly, the feature is available in the Central US EUAP, Italy North, Spain Central, and Norway East Azure regions.