The relationship between Speed, Price, and Fault Tolerance mostly determines the RAID level to use.
Of these three parameters, pick any two and you are all set.
- Fast and Fault Tolerant - RAID 1+0;
- Fast and Cheap, no Fault Tolerance - RAID 0;
- Cheap and Fault Tolerant - RAID 5 or RAID 6.
It may seem that RAID 5 and RAID 6 are expensive, but as the capacity of the array
and the number of disks increase, the overhead of the RAID 1+0, both in disks and
in controller ports, becomes significant.