RAID level 1 (mirroring) volume layout offers the following:

• Groups two or more disks as one virtual disk with the capacity of a single disk.

• Data is replicated on each disk, providing data redundancy.

• When a disk fails, the virtual disk still works. The data is read from the surviving disk(s).

• Better read performance, but slightly slower write performance.

• Because data is duplicated on two or more disks, RAID-1 is more "expensive" in terms of disk space.