[Taylor Long]

You would need two physical disks to build a RAID 1 array.

About RAID Modes

RAID 0 (FAST): RAID 0, is the fastest RAID mode. In a RAID 0 array, the available capacities of each drive are added together so that one logical volume mounts on the computer. It offers the best performance but no protection in the case that a drive fails.

Caution: In a RAID 0 array, if one physical drive in the array fails, the data of all drives becomes inaccessible because parts of the data have been written to all drives.

RAID 1 (SAFE): RAID 1 provides data safety since all data is written to each drive at the same time. In the event of a single drive failure, data remains available on the other drive. Due to the time it takes to write the data twice, performance is slightly reduced.

RAID 1 is a good choice when safety is more important than speed. However RAID 1 also reduces the available drive space by 50% due to the need to write each bit of data on each hard drive.

Here is a link to some of our RAID products.
https://www.lacie.com/products/range.htm?id=10061 ~TE, LaCie