Asus PCI-DA2200, User Manual

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ASUS GUI RAID Manager: RAID Levels
RAID 3
C-5
Block 1
Block 2
Block 3
Block 4
Block 5
Block 6
Block 7
Block 8
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Block 1
Block 3
Block 5
Block 7
Block 2
Block 4
Block 6
Block 8
Striping
Logical Drive
Physical Disks
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.
.
.
Mirror 1
Mirror 3
Mirror 5
Mirror 7
Mirror 2
Mirror 4
Mirror 6
Mirror 8
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Striping
Mirror
RAID 3
RAID 3 implements block striping with dedicated parity. This
RAID level breaks data into logical blocks, the size of a SCSI
disk block, and then stripes these blocks across several drives.
One drive is dedicated to parity. In the event a disk fails, the
original data can be reconstructed from the parity information.
In RAID 3, the total disk capacity is equivalent to the sum of the
capacities of all SCSI drives in the combination, excluding the
parity drive. Thus, combining four 1GB SCSI drives, for
example, would create a single logical drive with a total disk
capacity of 3GB. This combination appears to the system as a
single logical drive.
RAID 3 provides increased data transfer rates when data is being
accessed in large chunks or sequentially. However, in write
operations that do not span multiple drives, performance is
reduced since the information stored in the parity drive needs to
be re-calculated and re-written every time new data is written to
any of the data disks.