Performing a non-disruptive upgrade of data in a storage system that includes a plurality of storage devices and a storage controller, including: creating new data in a new data format, wherein the new data includes a reference to old data in an old data format, wherein system software in the storage system can utilize data in the new data format and the old data format; determining that a portion of the volume has changed; and responsive to determining that the portion of the volume has changed, updating the new data to include a reference to old data associated with a portion of the volume that precedes the changed portion of the volume, new data associated with the changed portion of the volume, and a reference to old data associated with a portion of the volume that follows the changed portion of the volume.