RAID

disk striping with parity

Process by which data is spread among multiple (at least three) drives, with parity information as well to provide fault tolerance. The most commonly implemented type is RAID 5, where the data and parity information is spread across three or more drives.

Disk Striping

Process by which data is spread among multiple (at least two) drives. Increases speed for both reads and writes of data. Considered RAID level 0 be- cause it does not provide fault tolerance. - half of the data goes to one hard drive and the other half goes to the second drive - advantage is speed - if either drive fails then you loose all the data

RAID 1 Disk Mirroring/ Duplexing

- Requires at least 2 drives - Ultimate safety but you loose space because the information is written twice

RAID

Redundant Array of Independent Disks

Disk duplexing

Type of disk mirroring using two separate controllers rather than one; faster than traditional mirroring. RAID 1

Disk Mirroring

The process of reading and writing data at the same time to two drives

RAID 0

A RAID array in which every time data is written to disk, a portion (block) is written to each disk in turn, creating a "stripe" of data across the member disks. RAID 0 uses the total disk space in the array for storage, without protecting the data from drive failure. (2)

RAID 10 (1+0)

Data is distributed as a stripe of mirrors requiring a minimum of four (4) disks to be implemented; good performance with fault tolerance (no parity blocks)

RAID 6

Nested stripped Mirrors is RAID 5 with extra Parity - needs at least 4 drives but you can loose up to two drives and still retain your data

RAID 5 (disk striping with distributed parity)

combines three or more disks in a way that protects data against the loss of any one disk; parity information is spread across all of the disks in the array instead of being limited to a single disk - not in favor due to huge data loss possibility