Areca ARC-5030 Series, Руководство пользователя

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INTRODUCTION
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1.7.2 RAID 1
RAID 1 is also known as “disk mirroring”; data written to one disk
drive is simultaneously written to another disk drive. Read per-
formance may be enhanced if the array controller can, in parallel,
accesses both members of a mirrored pair. During writes, there
will be a minor performance penalty when compared to writing
to a single disk. If one drive fails, all data (and software applica-
tions) are preserved on the other drive. RAID 1 offers extremely
high data reliability, but at the cost of doubling the required data
storage capacity.
1.7.3 RAID 10
RAID 10 is a combination of RAID 0 and RAID 1, combing strip-
ping with disk mirroring. RAID Level 10 combines the fast per-
formanceof Level 0 with the data redundancy of Leve1 1. In
this configuration, data is distributed across several disk drives,
similar to Level 0, which are then duplicated to another set of
drive for data protection. RAID 10 has been traditionally imple-
mented using an even number of disks, some hybrids can use an
odd number of disks as well. Figure 2 illustrates an example of a
hybrid RAID 10 array comprised of five disks; A, B, C, D and E. In
this configuration, each strip is mirrored on an adjacent disk with
wrap-around. In fact this scheme - or a slightly modified version
of it - is often referred to as RAID 1E and was originally proposed
by IBM. When the number of disks comprising a RAID 1E is even,
the striping pattern is identical to that of a traditional RAID 10,