Azure SQL Database Premium tier supports multiple redundant replicas for each database that are automatically provisioned in the same data centre within a region. This design leverages the SQL Server AlwaysON technology and provides resilience to server failures with 99.99% availability SLA and RPO=0. With the introduction of Azure Availability Zones, we are happy to announce that SQL Database now offers built-in support of Availability Zones in its Premium service tier. By placing individual database replicas in different availability zones, it makes Premium databases resilient to a much larger set of failures, including catastrophic data centre outages. The built-in support of Availability Zones further enhances the High Availability (HA) solutions in Azure SQL Database. For more information, see High availability and Azure SQL Database.
To take advantage of this capability, you simply select the zone-redundant option during database or elastic pool creation. You can also enable it for existing databases or pools. Once the zone redundant option has been enabled, Azure SQL Database will automatically reconfigure the database or pool without any downtime.
You can use the Azure portal to configure a database to be zone-redundant as illustrated on the following diagram.
Zone redundant Premium databases and pools are available in the following regions:
- Central US (general availability)
- France Central (general availability)
- West Europe (general availability)
- South East Asia (general availability)
Additional regions will be added over time.