Description: This object describes the type of a logic volume. The value 'virtual' means virtual devices are defined as sets of storage blocks from one or more physical array. This allows the creation of virtual devices that can be a portion of a larger physical array, or an aggregation of multiple physical array. The value 'direct' means direct devices are directly mapped SCSI devices. Because they are not virtualized, direct devices cannot take advantage of advanced storage options, such as mirroring, failover, replication, or snapshot copy. The value 'serviceEnabled' means service enabled devices are all maintained in a one-to-one mapping relationship(one physical array equals one logical device).