Avoiding "Storage-optimization" state when restoring RDS instance from snapshot

This seems somewhat obvious in hindsight, but the always lovely AWS support taught me that the "Storage-optimization" state occurs – during restore, anyway – when the snapshot's IO provisioning doesn't match that of the newly restored instance.  That is, the IO configuration of an RDS instance is saved when a snapshot is taken, and carried along with that snapshot for use during restore.

So if a snapshot was taken on an instance using GP2 storage of 500gb and your new instance is 1tb, or your provisioned IOPS are mismatched, you will enter the dreaded "Storage-optimization" state after your restore.  This reduces instance performance for an unknown period of time.

That's right, it could be minutes or it could be DAYS.  Avoid entering this state at all costs!