Starting from December 1, 2023, you can benefit from the new failover rights for Azure SQL Database, which allow you to reduce your licensing costs for disaster recovery scenarios. If you have a secondary database replica that is only used for disaster recovery purposes, and has no active workloads or connections, you can mark it as a standby replica. This way, you don’t have to pay for the vCores licensed in the primary database, and only pay for the compute and storage resources consumed by the secondary database.
What are the benefits of using standby replicas?
Using standby replicas can help you achieve the following benefits:
- Lower costs: You can save up to 50% on licensing costs for disaster recovery, as you only pay for the vCores used by the primary database, and not the secondary database.
- Simplified management: You can easily designate a secondary database as a standby replica by using the Azure portal, Azure PowerShell, or Azure CLI. You can also monitor the status and usage of your standby replicas from the Azure portal.
- Business continuity: You can still use the failover groups feature to manage the replication and failover of your databases across regions. You can also use the read-only listener endpoint to offload read-only workloads to the secondary database, if needed.
How do I enable standby replicas for my databases?
To enable standby replicas for your databases, you need to do the following steps:
- Create a failover group: A failover group is a logical grouping of databases that are replicated and failed over together. You can create a failover group by using the Azure portal, Azure PowerShell, or Azure CLI. You need to specify a primary server and a secondary server in different regions, and select the databases you want to include in the failover group. For more details, see Configure a failover group.
- Mark a secondary database as a standby replica: After creating a failover group, you can mark a secondary database as a standby replica by using the Azure portal, Azure PowerShell, or Azure CLI. You need to set the “Standby” property of the database to “True”. For more details, see Mark a secondary database as a standby replica.
What are the limitations and considerations of using standby replicas?
Before using standby replicas, you need to be aware of the following limitations and considerations:
- Licensing requirements: To use standby replicas, you need to have an active Software Assurance or Hybrid Benefit for your primary database. You also need to ensure that the primary and secondary databases have the same service tier, compute size, and storage size.
- Availability SLA: Standby replicas are not covered by the availability Service Level Agreement (SLA) of Azure SQL Database. If the secondary server or region becomes unavailable, you may not be able to fail over to the standby replica or restore it to another region. An availability SLA is a type of service level agreement (SLA) that specifies the percentage of time that a service is available and operational during a given period, excluding any planned or agreed downtime. For example, an availability SLA of 99.9% means that the service is expected to be up and running for at least 99.9% of the time in a month, which allows for about 43 minutes of downtime.
- Data loss risk: Standby replicas use asynchronous replication, which means that there may be some data loss in the event of a failover. You can check the replication lag of your standby replica from the Azure portal or by using the “sys.dm_geo_replication_link_status” dynamic management view.
For the announcement article, please visit: https://techcommunity.microsoft.com/t5/azure-sql-blog/license-free-standby-replica-for-azure-sql-database/ba-p/3973406.
Find the new clause in the December 2023 Product Terms here: https://www.microsoft.com/licensing/terms/productoffering/MicrosoftAzure/EAEAS#:~:text=SQL%20Server%20workloads.-,Azure%20SQL%20Database,to%20users%20or%20devices%20or%20otherwise%20run%20active%20SQL%20Server%20workloads.,-Azure%20Virtual%20Desktop.
For instructions on how to configure the standby replica, please visit: https://learn.microsoft.com/en-us/azure/azure-sql/database/standby-replica-how-to-configure?view=azuresql-db&tabs=azure-portal.
For software licensing information on Microsoft licensing programs, please visit: https://www.schneider.im/software/microsoft/.
Please contact us for free expert consultancy on your specific Microsoft agreements, more information and to request a quote.