Appendix 3 About Raid - Acard ARS-2018 User Manual

ARS-2018/2018E Manual

Appendix 3 About RAID

RAID (Redundant Array of Independent Disks) is a system composed of many hard
drives; that is, multiple physical drives form a single virtual drive to be recognized by
the system. The advantages of RAID technology are increasing the read/write speed
of a hard drive, achieving better data protection, and enlarging the capacity of a
single drive like Drive C, Drive D, etc. Different classes of RAID have different com-
position modes and different functions.
RAID 0 (Striping)
RAID 0 must be composed of a pair of hard drives at least. When data are written
into the whole hard drive, they will be equally striped and written into each hard
drive of the array. Thus the access speed becomes quicker. The effect of RAID 0 is
proportioned to the number of hard drives. More hard drives mean more read/write
heads, and therefore the speed is quicker. Though RAID 0 is quick in read/write
speed, it has no data redundancy, and accordingly has no fault tolerance.
It is suggested to compose RAID 0 with hard drives of the same capacity. Because
the capacity of striped disk array is the multiplication of the smallest hard drive
capacity with the number of hard drives. For example, a 100GB hard drive and a
120GB hard drive unite into RAID 0. The total capacity is 200GB (100GB×2).
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