Summary of "Azure Event Hubs Geo-Replication Reaches General Availability" (InfoQ, July 2025):
Microsoft has announced the General Availability (GA) of Geo-replication for Azure Event Hubs, now offered in both Premium and Dedicated tiers. This advancement brings enterprise-grade redundancy and availability to Event Hubs, a scalable event processing platform for large-scale data and events with low latency.
Key Features and Details
Primary-Secondary Model:
Geo-replication uses a primary-secondary architecture. One region (primary) remains active, serving producers and consumers. Secondary regions are "hot standbys," continuously mirroring the primary's configuration, but not directly accessible until promoted for failover.
Seamless Failover:
If a failure, maintenance, or outage happens in the primary region, the secondary can be quickly promoted to active (primary) with minimal downtime, ensuring business continuity.
Replication Consistency Modes:
Two main configurations are available:
Synchronous: Writes are acknowledged only after replication to a quorum of selected regions and zones, which can achieve RPO (Recovery Point Objective) = 0, implying no data loss.
Asynchronous: Offers configurable lag (higher performance/less consistency), suitable when minimal lag is acceptable.
Visibility & Metrics:
New monitoring capabilities give detailed insight into the health and status of replicas, helping admins know when failover is appropriate and maintain high availability.
Pricing:
Geo-replication charges depend on the primary region’s location. (Detailed pricing is available on the Azure Event Hubs site.
Comparison with Other Cloud Providers
Google Cloud Pub/Sub: Offers in-region high availability. Cross-region requires custom failover logic.
AWS (Amazon MSK/Kinesis/EventBridge): Uses external tools like MirrorMaker 2 for Kafka or requires users to architect complex cross-region redundancy for streaming, not natively integrated as in Azure EH.