RDS convert magnetic to gp3

You can convert your RDS instance from magnetic storage to gp3, but you cannot do this directly through a simple storage type modification. The error message you're receiving indicates that AWS doesn't support direct conversion from magnetic (standard) storage to SSD storage types through the modify operation.

Here are your options to migrate from magnetic to gp3 storage:

Option 1: Create a new instance from snapshot with gp3 When restoring from a snapshot, you should be able to specify a different storage type (gp3) during the restore process. This is different from modifying an existing instance. During snapshot restore, you can modify storage type settings even though the original snapshot used magnetic storage.

Option 2: Fresh instance with database import As you mentioned, you can create a new RDS instance with gp3 storage and migrate your SQL Server Express database using a .bak file import. This would give you a clean start with the desired storage type.

For SQL Server specifically: If you're using RDS for SQL Server, you have additional flexibility. You can add new storage volumes with gp3 storage type to your instance. For example, you could add a new gp3 volume and then move your databases to that volume, though this doesn't eliminate the magnetic volume entirely.

Recommendation: The cleanest approach would be to restore your snapshot to a new RDS instance and specify gp3 as the storage type during the restore operation. This should allow you to change the storage type while preserving your data. Make sure to specify the storage type, allocated storage, and if needed, provisioned IOPS and throughput settings during the restore process.

Given the May 2026 deprecation timeline, AWS will likely provide migration tools or automated processes closer to that date, but it's best to migrate proactively using one of the above methods.
Sources
Modifying settings for General Purpose SSD (gp3) storage - Amazon Relational Database Service
Working with storage in RDS for SQL Server - Amazon Relational Database Service

Hi,

There's a mention in this RDS doc - https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/CHAP_Storage.html#CHAP_Storage.Magnetic that

Magnetic storage (legacy, not recommended)
....
Doesn't allow you to convert to a different storage type when using the SQL Server database engine.

But given the AWS RDS team has contacted you about the scheduled change, I would suggest you contact AWS Support on the free support plan and inquire about RDS team's recommended option to proceed in SQL Server cases with magnetic volumes given their upcoming auto-migration plan as well.

Thanks.