>It seems like if we use at least 5HD with RAID 5, the data can be spread evenly between HD. Well, this is actually what I thought about RAID 5+0. But if we can also do it with RAID 5, then why RAID 5+0 exist ? I think I have to find out more about it, and get a clearer information.
RAID 5 requires at least 3 disks. My understanding is that the information is spread evenly, yes, but one hard disk is always used for redundancy. It seems that with 5 identical hard disks, the data would be spread among 4 hard disks, and the 5th. is used for redundancy (for the first bits; later the hard disks change places).
Perhaps RAID 5+0 is the name given by some manufacturers only, but I don't really know.
Hilmar.
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)