Azure SQL MI Fail over group configuration freezes?

Question

Hi thanks for the attention of my question

I am using Azure SQL MI.

I want to configure replication to a secondary region by setting up a fail over group.

However, since we are in production, it is important that there are no interruptions (including temporary freezes) when starting the Fail over group configuration.

Is there any interruption on the source DB server engine when configuring the fail over group ?

Answer 1

Hi @romero

When configuring a failover group for Azure SQL Managed Instance, there should be no interruption on the source DB server engine.

However, when establishing a failover group between managed instances, there's an initial seeding phase before data replication starts. The initial seeding phase is the longest and most expensive part of the operation. Once initial seeding completes data is synchronized, and only subsequent data changes are replicated. The time it takes for the initial seeding to complete depends on the size of data, number of replicated databases, workload intensity on the primary databases, and the speed of the link between the virtual networks hosting primary and secondary instance that mostly depends on the way connectivity is established. Under normal circumstances, and when connectivity is established using recommended global virtual network peering, seeding speed is up to 360 GB an hour for SQL Managed Instance. Seeding is performed for a batch of user databases in parallel - not necessarily for all databases at the same time. Multiple batches might be needed if there are many databases hosted on the instance.

Reference document https://learn.microsoft.com/en-us/azure/azure-sql/managed-instance/failover-group-sql-mi?view=azuresql

Thank You!