is-sis related parameters will automatically be set to true only for the volume where the volume efficiency setting is enabled. is-sis-volume can be true if the volume has clones OR dedupe enabled OR ...is-sis related parameters will automatically be set to true only for the volume where the volume efficiency setting is enabled. is-sis-volume can be true if the volume has clones OR dedupe enabled OR a snap restore has happened on the volume. Users can promote the deprioritized volume to re-participate in an automatic background deduplication using the volume efficiency promote command available at the advanced privilege level.