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RAID (Redundant Array of Independent Disks) is a method for computer data storage
schemes that divide and/or replicate data among multiple hard drives. RAID can
�e designed to provide increased data relia�ility (fault tolerance) or increased I/O
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(input/output) performance, or �oth. The mother�oard comes with the Intel
PCH. The
There are three major key concepts in RAID:
1. Mirroring : The copying of data to more than one disk;
3. Error correction : Where redundant data is stored to allow pro�lems to �e detected
Different RAID levels use one or more of these techniques, depending on the system
requirements. The main aims of using RAID are to improve relia�ility, important for
protecting information that is critical to a �usiness, for example a data�ase of customer
orders; or where speed is important, for example a system that delivers video on
demand TV programs to many viewers.
with using more disks is that it is more likely that one will go wrong, �ut �y using
error checking the total system can �e made more relia�le �y �eing a�le to survive
and repair the failure. Basic mirroring can speed up reading data as a system can
read different data from �oth the disks, �ut it may �e slow for writing if it insists that
performance, where it allows sequences of data to �e read off multiple disks at the
same time. Error checking typically will slow the system down as data needs to �e
read from several places and compared. The design of RAID systems is therefore a
compromise and understanding the requirements of a system is important. Modern
RAID is often used in high availa�ility systems, where it is important that the system
keeps running as much of the time as possi�le.
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