SIIG Serial ATA PCI RAID Manual de usuario descargar pdf (Pagina 12)

RAID

2-1

Chapter 2

RAID Arrays

2-1 RAID Overview

Historically, the cost of implementing RAID in the small office

or home office environment has not been cost effective. When first

developed, RAID was an acronym for Redundant Array of

Inexpensive Drives. This, however, was changed to Redundant

Array of Independent Disks, for it was the more expensive

SCSI disk drives with superior performance and capacity which

captured the dominant share of the RAID market. But today’s

technology is changing, and the performance/capacity gap

between SCSI and ATA is quickly getting smaller. With the

increased performance of ATA/100 host controllers and higher

capacity ATA drives coming to market, the time is right to put ATA

software RAID to work in the small office, home office,

environment and CMD Medley is just the software to do that.

RAID was designed to greatly enhance two main categories of data

storage, performance and data integrity. RAID 0 (striping) can

actually increase the performance of sustained data transfer rates.

The second benefit of RAID is data redundancy. With RAID 1

(mirroring) an identical image of your data is placed on another

drive or set of drives. Should your main drive fail your data is

secure and available from the mirrored second drive.

For performance and data redundancy, use RAID 0+1

(mirror + stripping).

2-1.1 RAID 0 (striping)

Striping is a performance oriented, non-redundant data

mapping technique. It does not provide fault tolerance so it

will not protect your data. Data is spread accross all disks

in the stripe set allowing multiple I/O operations enhancing

performance by taking advantage of today bus mastering

technology. The drawback is when one disk fails the whole

group fails. Two to four disks are required for striping.

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SIIG Serial ATA PCI RAID Manual de usuario Pagina 12