You need to migrate a set of databases that use distributed transactions from on-premises SQL Server. Which option should you choose?

Migrating databases that utilize distributed transactions can pose unique challenges, primarily due to the way these transactions interact across different systems. Azure SQL Managed Instance is the appropriate choice for this scenario because it provides a fully managed SQL Server environment that retains compatibility with the SQL Server features necessary for distributed transactions, such as Distributed Transaction Coordinator (DTC).

Managed Instances support the full SQL Server feature set, making it easier to migrate applications that rely on specific SQL Server capabilities, including those using distributed transactions. This compatibility ensures that existing applications can function with minimal changes post-migration.

The other options have limitations that make them unsuitable for this specific requirement. Azure SQL Database, while a powerful option, does not support all features of SQL Server, particularly those involved with distributed transactions. Azure Database Migration Service is a tool to assist in the migration process itself but does not relate to the environment in which the databases will operate post-migration. SQL Managed Backup is focused on backup and restore processes and does not pertain to transaction management or migration strategies. Therefore, opting for Azure SQL Managed Instance aligns best with the requirement of migrating databases using distributed transactions.