Installation guide

Software Operation Manual
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1.2.4 RAID 3
RAID 3 provides disk striping and complete data redundancy though a
dedicated parity drive. RAID 3 breaks up data into smaller blocks, calculates
parity by performing an exclusive-or on the blocks, and then writes the blocks to
all but one drive in the array. The parity data created during the exclusive-or is
then written to the last drive in the array. If a single drive fails, data is still
available by computing the exclusive-or of the contents corresponding strips of
the surviving member disk. RAID 3 is best for applications that require very fast
data- transfer rates or long data blocks.
1.2.5 RAID 5
RAID 5 is sometimes called striping with parity at byte level. In RAID 5, the parity
information is written to all of the drives in the controllers rather than
concentrated on a dedicated parity disk. If one drive in the system fails, the
parity information can be used to reconstruct the data from that drive. All drives
in the array system can be used to seek operation at the same time, greatly
increasing the performance of the RAID system. This relieves the write
bottle-neck that characterizes RAID 4, and is the primary reason that RAID 5 is
more often implemented in RAID arrays.