Asus PCI-DA2200, User Manual

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ASUS GUI RAID Manager: RAID Levels
RAID 1
C-3
multiple disks. Furthermore, for I/Os that do not span more than
one drive, read/writes to different drives can be processed
concurrently.
Block 1
Block 2
Block 3
Block 4
Block 5
Block 6
Block 7
Block 8
.
.
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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RAID 1
RAID 1 implements disk mirroring where a copy of the same
data is recorded onto two sets of striped drives. By keeping two
copies of data on separate disks or arrays, data is protected
against a disk failure. If, at any time, a disk on either side fails,
the good disks can provide all of the data needed, thus
preventing downtime.
In disk mirroring, the total disk capacity is equivalent to half the
sum of the capacities of all SCSI drives in the combination.
Thus, combining four 1GB SCSI drives, for example, would
create a single logical drive with a total disk capacity of 2GB.
This combination of drives appears to the system as a single
logical drive.
RAID 1 is simple and easy to implement; however, it is more
expensive as it doubles investment required for a non-redundant
disk array implementation.