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Chapter 1 Introduction
General RAID Concepts
General RAID Concepts
Correct installation of the disk array requires an understanding of
RAID technology and the concepts described in this section.
Defi nition
RAID is an acronym of Redundant Array of Independent Disks .A RAID is a Disk Array in which
part of the storage capacity is used to record redundant information about the user data stored on
the remainder of the storage capacity. The redundant information enables regeneration of user
data in the event that one of the Array’s member Disks or the access path to it fails.
Benefi ts of RAID
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Secure Data RAID is an emerging storage technology with the potential to revolutionize
the data storage technology. A typical RAID unit contains a set of disk drives, typically two
to six, which appear to the user to be equivalent to a single large capacity disk drive. The
remarkable benefi t of disk array is that if any single disk in the RAID fails, the system and
array still continues to function without loss of data. This is possible because the redundancy
data is stored on separate disk drives and the RAID can reconstruct the data that was stored
on the failed disk drive.
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Increases system performance As the effective seek time for fi nding data on a disk can
potentially be reduced by allowing multiple simultaneous access of different data on different
disks. Utilizing parallel reads and writes of the data spread across the disks in the array, the
data transfer rate can be increased signifi cantly over that of a single disk.
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Easy RAID system maintenance is typically simplifi ed because it is easy to replace individual
disks and other components while the system continues to function. (Hot swap support )
