Raid Types RAID Redundant Array of Independent Disks

Raid Types RAID (Redundant Array of Independent Disks) RAID provides a method of accessing multiple individual disks as if the array were one large disk, spreading data access out over these multiple disks, thereby reducing the risk of losing all data if one drive fails, and improving access time.

Raid 0 �RAID Level 0: "Disk Striping" �RAID 0: Also known as "Disk Striping", is technically not a RAID level since it provides no fault tolerance. (Parity) Data is written in blocks across multiple drives, so one drive can be writing or reading a block while the next is seeking the next block. �The advantages of RAID 0 is it’s high level of I/O performance because the I/Os are spread across multiple channels and drives. �Because RAID 0 offers no fault tolerance, if one drive should fail, this will result a loss of all your data. This should never be used in a environment where data is mission critical. �*RAID 0 requires a minimum of two drives to initiate.

Raid 0:

Raid 1 �RAID 1: Known as "Disk Mirroring" provides redundancy by fully duplicating drive data to all other drives in the array. If one drive fails, the others contain exact duplicate of the data and the RAID can switch to using the mirror drive with no lapse in user accessibility. The disadvantages of mirroring are no improvement in data access speed, and capacity is low. However, it provides the best protection of data since the array management software will simply direct all application requests to the surviving disk members when a member of disk fails.

Raid 1:

Raid 5 �When RAID level 5 technology is combined with cache memory to improve it’s write performance, the result can be used in any applications where general purpose disks would be suitable. �For read only or read mostly application I/O loads, RAID level 5 performance should approximate that of a RAID level 0 array. In fact, for a given user capacity, RAID level 5 read performance should normally be slightly better because requests are spread across one more members than they would be in a RAID level 0 array of equivalent usable capacity. �RAID level 5 requires a minimum of 3 drives to initiate.

Raid 5: