INTRODUCTION
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data blocks.
1.7.5 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 being 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 for seek operations at the same time,
greatly increasing the performance of the RAID system. This
relieves the write bottleneck that characterizes RAID 4, and is the
primary reason that RAID 5 is more often implemented in RAID
arrays.
1.7.6 RAID 6
RAID 6 provides the highest reliability, but is not yet widely
used. It is similar to RAID 5, but it performs two different parity
computations or the same computation on overlapping subsets
of the data. RAID 6 can offer fault tolerance greater than RAID
1 or RAID 5 but only consumes the capacity of 2 disk drives for
distributed parity data. RAID 6 is an extension of RAID 5 but uses
a second, independent distributed parity scheme. Data is striped
on a block level across a set of drives, and then a second set of
parity is calculated and written across all of the drives.
Summary of Contents for ARC-5030 Series
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