If you want to clone data, Backup requires a specific pool to receive the clone data, and a minimum of two devices, one to read the source volume and the other to write the clone. If you do not associate data to be cloned with a customized clone pool, Backup automatically uses the Default Clone pool. You must mount an appropriately labeled volume on a separate storage device for the cloning process to proceed smoothly. See "Cloning " for more information on the Backup cloning feature.