Solved RAID 1 - 2tb and 640gb Tags: NAS / RAID Caviar Storage Last response: July 3, 2012 12:01 AM in Storage Share sirgogo June 26, 2012 6:09:52 AM Hi all, I've never used RAID before, but I was interested in RAID 1. I have two drives: Drive A - 640 gb Caviar Black Drive B - 2 tb Caviar Green What I want to do is create a backup (RAID1) of my Drive A onto my Drive B, and use the remaining space as a data partition. So I want 3 partitions: A - Drive A - 640 gb (Primary) B - Drive B - 640 gb (Backup) C - Drive B - 1408 gb (Misc data) Is this possible? More about : raid 2tb 640gb Best solution Dereck47 a c 525 G Storage June 26, 2012 11:06:11 AM No. This is how you calculate the size of a RAID-1 array: Storage Efficiency: 50% if drives of the same size are used, otherwise (Size of Smaller Drive / (Size of Smaller Drive + Size of Larger Drive) ) said:Storage Efficiency: 50% if drives of the same size are used, otherwise (Size of Smaller Drive / (Size of Smaller Drive + Size of Larger Drive) ) So the total size of your RAID-1 array with those 2 drives would be 633.6GB. Your drives need to be equal size for maximum storage efficiency. Share sirgogo July 3, 2012 12:01:47 AM Best answer selected by sirgogo. m 0 l Can't find your answer ? Ask ! Publish Related resources RAID0 - 4 640GB Drives - 2TB Limit Forum Solved2tb hardrive vs 2 1tb hardrives in raid Forum SolvedWhich is faster 2x 1TB WD Red (RAID 0) or 1x 2TB WD Black Forum SSD + 2TB Storage + RAID5 on 4x 1TB Forum 2 x 2TB vs 1 x 4TB as storage. No Raid. Forum 2TB caviar black vs 2x1TB caviar blue in raid 0??? Forum Solved2TB HDD vs 2x1TB HDDs in RAID 0 massive? Forum RAID0 with a 1TB and 2TB HDD ?? WD Caviar black Forum 2TB hard drive and 500gb HDD can i raid1 500gb n use the rest Forum 1 ssd and two 2tb in raid 1 Forum 2x Seagate 1TB in RAID 0 vs 1x WD Black 2TB FOR STORAGE Forum Ultimate HTPC - core i7 950 - Ceton 4 - GTS 450 - 2TB + 640GB HDD - Bl Forum SSD for OS + 2TB Raid 1 with 1TB USB backup feedback Forum 2 X 1TB Raid 0 Vs 2TB Forum One 2TB or two 1TB in Raid 0 for gaming? Forum WD 2TB vs 2 x Seagate 1TB in RAID0 Forum Raid5: 6x 1TB vs 4x 2TB Forum RAID 1+0 Larger than 2TB Forum Seagate 2TB vs WD 2x1TB Raid SATA3, Which one? Forum 2TB RAID 1: which drives? Forum More resources Read discussions in other Storage categories Hard Drives DVD Drives DVD Writers Optical Media Flash Media NAS/RAID SSD Western Digital !