Having 10 disks, I want to use one quarter of each for a big raid 0 array and the remaining 3/4 of each for a raid 1 array having a backup of the raid 0 array. I can't do a raid 1 or both array, that would slow down the raid 0 speed. I need 99.9% reads, mostly concurrent. Raid 1 on 2 disks doesn't seem to double the read speed to me. This is why I want a raid 0.
Sorry for hitting your brain. It wasn't my goal. Also sorry for my English. Point is that in raid 10 for 10 disks the read speed is 5*speed of the single drive, while in raid 0 it's 10*single drive speed. I was wondering if there was a way to combine 2 array, reading data only from the raid 0, while keeping the raid 1 for redundancy. I'm again sorry for how bad I explain myself, really. – cedivad 10 mins ago