Types of RAID

There are at least nine types of RAID plus a non-redundant array (RAID-0):

RAID 0 (Striping / Span)

1. Scripting with no redundancy.
2. Best performance but no fault tolerance.

RAID 2 (Mirroring)

1. At least 2 drives are used to duplicate the storage of data.
2. No scripting.
3. Read performance is improved as either disk can be read at the same time.
4. Provides the best performance and the best fault-tolerance in a multi-user system.

RAID 3

1. This type uses striping and dedicates one drive to storing parity information.
2. The embedded error checking (ECC) information is used to detect errors.
3. Cannot overlap I/O.
4. Best for single-user systems with long record applications.

RAID 4 (Striping with Parity)

1. Uses block-level striping with a dedicated parity disk.
2. This allows you to take advantage of overlapped I/O for read operations
3. No I/O overlapping is possible, since all write operations have to update the parity drive.

RAID 5

1. Includes a rotating parity array reducing the write limitation in RAID 4.
2. All read and write operations can be overlapped.
3. Stores parity information but not redundant data
4. Requires at least three and usually five disks for the array.
5. Best for multi-user systems in which performance is not critical or which do few write operations.

RAID 6

1. Similar to RAID-5 but includes a second parity scheme that is distributed across different drives.
2. Offers extremely high fault and drive failure tolerance.

RAID 10 (Striping with Mirroring (RAID 0 + 1 ))

1. Scripting and mirroring combined