Sans Digital Towerraid TR4UTP Manual de usuario descargar pdf (Pagina 7)

Figure 1: Dividing Disks into Members

2.3 RAID LEVELS IN DETAILS

2.3.1 Disk Striping (RAID 0)

Striping is a performance-oriented, non-redundant data mapping technique. While Striping is discussed as a RAID Group

type, it is does not provide any fault tolerance. With modern SATA and ATA bus mastering technology, multiple I/O

operations can be performed in parallel, enhancing data throughput. Striping arrays use multiple disks to form a larger

virtual disk. The figure below illustrates a three-disk stripe set. Stripe one is written to disk one, stripe two to disk two,

and so forth. RAID 0 sets can be comprised of two, three, or four drives. If the sizes of the disk segments are different, the

smallest disk segment will limit the overall size of the RAID Group.

Stripe2

Stripe5

Stripe8

Stripe11

Stripe0

Stripe3

Stripe6

Stripe9

Stripe1

Stripe4

Stripe7

Stripe10

2.3.2 Disk Mirroring (RAID 1)

Disk mirroring creates an identical twin for a selected disk by having the data simultaneously written to two disks. This

redundancy provides instantaneous protection from a single disk failure. If a read failure occurs on one drive, the system

reads the data from the other drive. RAID 1 sets are comprised of two drives, and a third drive can be allocated as a spare

in case one of the drives in the set fails. If the sizes of the disk segments are different, the smallest disk segment will limit

the overall size of the RAID Group.

k 1

k 2

k 1

k 2

2.3.3 Disk Mirroring and Striping (RAID 10)

RAID 10 combines the features of both RAID 0 and RAID 1. Performance is provided through the use of Striping (RAID 0),

while adding the fault tolerance of Mirroring (RAID 1). The implementation of RAID 10 requires four drives. The drives are

assigned as two sets of striped pairs.

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Sans Digital Towerraid TR4UTP Manual de usuario Pagina 7