CertiGuide to A+ (A+ 4 Real)  9  Chapter 10: The Small Computer System Interface, SCSI       9  RAID            9  RAID Levels

RAID Levels 1 RAID-1

RAID-0¹²¹ provides striping for performance but offers NO fault tolerance. RAID-0 is not defined in the original Berkeley paper. RAID-0 is not true RAID because it offers no redundancy. Of all the RAID levels, RAID-0 offers the greatest performance gain.

RAID-0 is known as data striping. Data is divided into smaller, equally sized pieces and simultaneously written to or read from multiple drives, as shown in the example of Figure 404. The data is broken into blocks. Each block is then written to a separate drive. Each drive can write or read its assigned block at the same time as the others in the array, so the operation takes 1/5 the time it would for a single drive.

I/O bandwidth is increased by simultaneously accessing multiple data paths. RAID-0 offers no data redundancy; therefore, the loss of a single drive will result in the loss of all data in a striped set. RAID-0 should never be used in mission critical environments and frequent data backups are recommended.

RAID-0 is a good choice for high bandwidth applications such as video pro-duction, editing, and pre-press applications. RAID-0 will be of benefit in any environment where read/write performance is important, but ongoing data protection is less of a concern.

RAID Levels 1 RAID-1