The encryption at rest requires creating a new volume as you mention. Since the encryption is at rest, there is no real way to encrypt on the fly if you will. There aren't any current plans to change this functionality. If you bought another SAN, usually you would specify encrypted drives up front. In that case you would be migrating from one SAN to another. With Nimble, we added that functionality with software. Hope this helps. Feel free to reach out if you need more info.