The Amazon docs state that you cannot increase the storage allocated to a SQL Server RDS instance:
Note that you cannot change the storage capacity nor the type of storage for a SQL Server DB instance due to limitations of striped storage attached to a Windows Server environment.
Oh well, so I guess you take a snapshot and restore it to a new instance with more storage... except that seems to be impossible too:
Amazon RDS does not support changing the storage configuration for a Microsoft SQL Server DB instance when restoring from a DB snapshot.
That quote may refer to changing between general SSD and provisioned I/O, but there's no
--allocated-storage parameter for
restore-db-instance-from-db-snapshot, so it does seem to be impossible when restoring a snapshot. For that matter, simply specifying a new number of IOPS gives an error:
Cannot restore this instance based in Windows OS because the request has a different iops than the backup.
What is the most convenient way to increase the storage space allocated to a SQL Server instance? Is there nothing better than Database Migration Services in this situation?
Amazon support confirmed that S3 and DMS are the only options for SQL Server.
This question has been raised on SE. I've opened this question provisionally; if there's a consensus in Meta that we should not duplicate DBA questions which exist elsewhere on SO, I'll delete this one.
2019: Some time since I raised this question, it seems that Amazon lifted some restrictions. I was able to resize a SQL Server instance without taking any special steps: just edit the config and allow it to reboot.