Yes, it is RAID-1 and not only the Canadian Military but our own uses this as the preferred means of a system backup (we also use off-site storage as well as open-file tape backup). Below is a quick and short breakdown of the two (in my opinion alone!) most beneficial types of RAID:

RAID Level 1 provides redundancy by writing all data to two or more drives. The performance of a level 1 array tends to be faster on reads and slower on writes compared to a single drive, but if either drive fails, no data is lost. This is a good redundant system and provides the greatest fault tolerance, since only two drives are required; however, since one drive is used to store a duplicate of the data, the cost per megabyte is high. (Also called mirroring)

RAID-1 is the choice for performance-critical, fault-tolerant environments. Also, RAID-1 is the only choice for fault-tolerance if no more than two drives are desired.
RAID-5 is the best choice in multi-user environments which are not write performance sensitive. However, at least three, and actually usually five drives are required for RAID-5 arrays.