A RAID 10 configuration requires a minimum of four disks, and stripes data across mirrored pairs. As long as one disk in each mirrored pair is functional, data can be retrieved. If two disks in the same mirrored pair fail, all data will be lost because there is no parity in the striped sets.
RAID 10 provides redundancy and performance, and is the best option for I/O-intensive applications. One disadvantage is that only 50% of the total raw capacity of the drives is usable due to mirroring.