iR2940-6S-S2D possesses the space for 2 x 2.5” SATA HDDs with RAID 1 function and 3 x 3.5” HDDs with RAID 5 function which is able to store the O.S. and data separately, not only keeps system running constantly but also avoid the data loss caused by HDD failure. Besides, with two independent SATA ports for each access to RAID 1 and RAID 5, making the O.S. and data access do not affect each other which is the ideal and suitable internal RAID solution for SMEs MIS department, monitoring system and workstation operating system!