1.5. Connecting Serial ATA Drives
You can connect up to 4 serial ATA drives to the controller. The serial ATA ports
J3 and J4 can optionally be used as external connectors. As the serial ATA ports are
mounted in parallel respectively, the external (J3B or J4B) and the internal ports (J3
or J4) must not be used at the same time. Four special serial ATA cables are included
in the package of your RAID controller.
1.6. RAID Levels (Redundant Array of Independent Disks)
Fundamentally, a RAID unit is called a “RAID array”. The individual hard disks
combined in a RAID array are seen as one single hard disk by your PC. An array
consists of at least two hard disks. The hard disks found in a RAID array are commonly
called “members”. Further characteristics of the individual modes are described below.
1.6.1.
Non-RAID Mode (Single Disk Mode)
This mode treats each hard disk as an independent device.
1.6.2.
Striping (RAID 0)
Data blocks are written alternately on the hard disks. The fact that the data
blocks are spread on two or more drives and that the controller is able to address
two hard disks at the same time leads to a considerable increase in performance
and to an ideal concentration of capacity. Failure of one member of the array
affects the whole array. If possible, the hard disks should be identical, otherwise
the size and performance of the smallest hard disk is applied as a standard for the
other ones.
1.6.3.
Mirroring (RAID 1)
The data blocks are duplicated by the RAID controller and written in parallel
(or mirrored) on two hard disks at the same time. Mirroring data on two hard disks
considerably increases data availability as well as data security. As the controller
is able to address two hard disks at the same time, performance practically
remains constant as opposed to one single hard disk. In case of failure of one hard
disk due to a fault, the other hard disk assumes its function without data being lost.
The faulty hard disk can then be exchanged and the data from the working hard
disk copied onto the new one, so that complete redundancy of data is reestablished.
1.6.4.
Striping / Mirroring (RAID 0+1)
A combination of the two RAID types mentioned above. The array consists
of four hard disks; data blocks are alternately written on one pair of hard disks
respectively (striping), which increases performance. To increase data security,
the data blocks are at the same time written on the other pair in parallel, so that
complete data security is guaranteed.
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Manual
