Introduction RAID is a method of using multiple hard drives to act as one. There are two purposes of RAID: Expand drive capacity: RAID 0. If you have 2 x 500 GB HDD then total space become 1 TB. Prevent data loss in case of drive failure: For example RAID 1, RAID 5, RAID 6, and RAID 10. There are three ways to create a RAID: Software-RAID: Where the RAID is created by software. Hardware-RAID: A sp