A system and method for exposing volumes with underlying read-write mediums to user operations. When a medium is in the process of being migrated to a storage array, a volume which relies on the medium can be exposed to user operations (e.g., snapshots, read and write operations) once the portions of the medium which underlie the volume have been migrated. The volume can be exposed to user operations while one or more other portions of the medium are unfilled and while the medium is in an intermediate read-write state.