RAID 10/1+0
RAID 1+0 is just what it sounds like, striped mirrors.
4 disks are required for a RAID 10 array, as you will first create two mirrors, then stripe these(2+2).
RAID 10 is very expensive, especially as it begins to scale, as you will need to add disks in pairs, but also offers very high performance, both write and read.
In a RAID 10 array with 6 disks, you can lose up to 3 disks in a best case scenario without losing data.
Mirror 1 Mirror 2 Mirror 3 -
Disk1 Disk2 Disk3 - Stripe 1
Disk4 Disk5 Disk6 -
In the above example, disks 1, 2, and 6 could all break, and you would still have an intact array, since none of the mirrors have broken.
It is a bit of luck involved however, as if Disks 1&4 were to break, the array will break, as Mirror 1 would break.
RAID 10 is best used where both performance and redundancy is needed, such as a high performance database.