Solution:

The advantage of this function is to expand fault tolerance of HDD. With this function, the HDD fault tolerance is expanded to 2 hard disks. For example, if user configures 8 hard disks as two logical drives with RAID 5, and groups up these logical drives via "Logical volume" function. When this volume is mapped to host channel, only one hard disk is seen by OS. And it is same to one RAID 5 logical drive with 8 hard disks under OS. In general, this function is called RAID level 50.