Edge10 DAS401 사용자 가이드
2.3.4 PARITY RAID (RAID 5)
Parity or RAID 5 adds fault tolerance to Disk Striping by including parity information with the data. Parity RAID
dedicates the equivalent of one disk for storing parity stripes. The data and parity information is arranged on the
disk array so that parity is written to different disks. There are at least 3 members to a Parity RAID set. The
following example illustrates how the parity is rotated from disk to disk. The following example illustrates how the
parity is rotated from disk to disk.
Parity RAID uses less capacity for protection and is the preferred method to reduce the cost per megabyte for
larger installations. Mirroring requires 100% increase in capacity to protect the data whereas the above example
using three hard drives only requires a 50% increase. The additional required capacity decreases as the number
of disks in the group increases (i.e., 33% for four drives or 25% for five drives).
In exchange for low overhead necessary to implement protection, Parity RAID degrades performance for all write
operations. The parity calculations for Parity RAID may result in write performance that is somewhat slower than
the write performance to a single disk.
2.3.5 CONCATENATION (COMBINE DRIVE)
The Concatenated mode combines multiple disks or segments of disks into a single large volume. It does not
provide any data protection or performance improvement but can be useful for utilizing leftover space on disks.
Concatenation allows the segments that make up the volume to be of different sizes.
2.3.6 SINGLE DRIVE / SEGMENT
The single drive is a virtual disk that can either be an entire disk drive or a segment of a single disk drive. Single
drive is the “Contiguous” configuration option when creating RAID Groups (or sets) in the SATARAID5 software.
DAS401 User’s Manual
Ver.071015
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