There are at least nine types of RAID plus a non-redundant array (RAID 0):
- RAID 0 – Stripes data across multiple disks, no parity, no redundancy.
- RAID 1 – Disk mirroring, writes data to two identical partitions on separate hard disks creating a full backup. Separate controllers are used.
- RAID 2 – Writes data across multiple disks with error checking.
- RAID 3 – Stripes data one byte at a time and has a dedicated parity drive (for error checking).
- RAID 4 – Stripes data one sector at a time and has a dedicated parity drive (for error checking).
- RAID 5 – Stripes data and parity across multiple disks (at least 3). By mixing the parity across multiple disks a separate parity disk is not required and yet full data redundancy is achieved.
*Note with RAID 5 on an NT box the BOOT and SYSTEM partitions cannot be located on a RAID 5 disk array.