WHAT IS RAID 0+1?
RAID 0+1 uses a minimum of four drives. Additional drives must be added in even numbers. If four drives are used, a pair is first striped as in a RAID 0 and then is mirrored as in RAID 1. The total storage capacity is calculated by summing the storage capacity of all the drives in the array and dividing it in half. For this reason, RAID 0+1 can be very expensive. This level does offer increased performance over some of the other RAID levels due to the striping that takes place. Because there is a mirrored copy of the stripe set, a RAID 0+1 array allows the failure of one or more drives as long as the failure of each occurs in the same stripe set. When this type of drive failure occurs, the RAID 0+1 essentially becomes a RAID 0 and is vulnerable to drive failures in the mirrored copy. A RAID 0+1 array is typically used in servers that demand high performance. It is also used in high capacity external hard drives. For more information about devices with built-in RAID 0+1 technology, clic
