Building blocks
Design goal
Keep the database recoverable across a regional event without assuming database replication alone will make the application usable after failover.
Architecture
Azure SQL provides service-managed local high availability. Regional recovery can use active geo-replication for individual databases or failover groups for grouped databases and stable listener endpoints.
Architecture decisions
Choose replication scope deliberately
WhyUse active geo-replication for database-level control and failover groups when grouped failover and stable endpoints are required.
Trade-offDatabase-level replication gives precise control, while grouped failover simplifies application endpoints; the choice changes failover coordination, cost, and operational flexibility.
Design the whole dependency chain
WhySecondary-region networking, identity, secrets, and application configuration must work after database failover.
Trade-offPreparing the full secondary environment improves recovery confidence, but means paying for and maintaining more than the database replica alone.
Security
Protect the control and data paths deliberately. Use contained users or appropriately synchronized identity configuration, private connectivity where required, and equivalent network controls in both regions.
Availability
Design for the failure domain that must be survived. Use service-tier capabilities and zone redundancy where available to reduce local failure impact before invoking regional DR.
Disaster recovery
Treat regional recovery as a separate operating state. Define planned and forced failover procedures, expected data-loss behavior, failback, and application connection-string strategy.
Cost drivers
- Database service tier and vCores/DTUs
- geo-secondary compute
- backup retention
- data transfer
- monitoring
Design assumptions
- Application supports retry/failover behavior
- Secondary region is approved
- RPO/RTO are defined
Implementation plan
- Define the acceptable data loss, recovery time, failover scope, and application connection behavior before selecting a replication pattern.
- Choose the database/service tier and configure the secondary database or failover group in a region that supports the required features.
- Prepare Private Endpoints, DNS, firewall rules, identities, keys, and dependent services in both regions so failover does not stop at the database.
- Point applications at the stable listener/connection pattern appropriate to the chosen design and define read-only routing only if it is needed.
- Configure replication/failover monitoring, then execute planned failover and failback tests while measuring application reconnection and data-loss behavior.
Validate the design
- Perform a planned failover and confirm the application reconnects through the intended stable endpoint.
- Verify authentication, Private DNS, firewall/private-endpoint paths, and dependent services work in the secondary region.
- Measure application recovery time and observed data-loss behavior against the agreed RTO/RPO.
- Fail back during a controlled test and confirm monitoring reports replication health before returning to normal operations.