Raid 1 duplicates 2 disks, so with 2 disks (of 500GB (465GB-ish effectively)), you get 1 disk in usable space. Raid 5 has a parity drive, which means 1 drive in your raid 5 is lost to parity, which is used in case of a drive failure to reconstruct the data on the missing (failed) drive. So with 3 physical disks (the absolute minimum for raid 5), you get 2 disks in usable space. So your numbers are exactly what I'd expect to see except that I don't think you checked the disk size correctly when you selected raid 0, as a raid 0 would give you the full space of the smallest drive times the number of drives in the raid 0. Note that raid 0 has zero redundancy, so if you lose 1 drive you lose all data, which is why it's only useful in situations where absolute performance is required at the sacrifice of data availability (and you have a very good backup plan in place or don't care if the data is lost when a drive even just 'glitches').
 Hi All, i've finally set my dell MD3600i; what i don't understand's i'm using 3 physicals Drivers of 3.725,524GB (11.176,569GB) and 2 of  465,261GB (930.522GB) I've set it on RAID 5 the 3 disk but i can only see and use 7,451.045 GB and i can see that this space's associated with all thoses disk. [IMAGE] Even when if i set it on RAID 0, it's look like i can use space of one disk.  Thanks for your support
Driver Space Missing on Dell MD3600i???