Migrate Azure SQL Managed Instance to Amazon RDS for SQL Server Using BYOM

Amazon RDS for SQL Server with Bring Your Own Media (BYOM) allows customers to reuse existing SQL Server licenses from Microsoft’s License Mobility through Software Assurance benefit. This eliminates the need to pay for licenses twice when migrating off Azure SQL Managed Instance to a fully managed AWS database service.

The migration walkthrough details a full-backup cutover method, where a COPY_ONLY backup is taken from the source, moved to Amazon S3, and natively restored on Amazon RDS. This method's downtime is proportional to database size, making it suitable for databases that can tolerate a maintenance window. AWS Database Migration Service (DMS) is mentioned as an alternative for lower-downtime migrations using change data capture, though it is out of scope for this guide.

Successful migration requires SQL Server licenses with active Software Assurance, the RTM ISO uploaded to Amazon S3, and an S3 bucket for backup files in the target AWS Region. An Amazon RDS option group with SQLSERVER_BACKUP_RESTORE and an IAM role for S3 access are also necessary. Access to both the Azure SQL Managed Instance and a target Amazon VPC, along with a management host, are also prerequisites.

The guide provides step-by-step instructions for exporting the database using SQL Server Management Studio (SSMS), including handling Transparent Data Encryption (TDE). It outlines how to disable TDE, create credentials for Azure Blob Storage with a Shared Access Signature (SAS) token, and take a COPY_ONLY full backup to Azure Blob Storage.

After exporting, backup files are transferred to an Amazon S3 bucket in the same AWS Region as the target RDS instance. For one-time migrations, `azcopy` with the AWS CLI is suggested, while AWS DataSync is recommended for production or repeatable transfers due to its built-in verification and support for Azure Blob Storage.

The final major step involves deploying the BYOM instance through the Amazon RDS console. This includes selecting the SQL Server edition and version, choosing the 'Bring your own media' license model, and pointing to the RTM media in Amazon S3. The console automatically creates the BYOM engine version during instance creation, followed by configuring instance class, storage, and networking.