Connection Of The Securaid114 Disk Array Controller (Scsi) - NEC Express5800 110Ej User Manual

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Connection of the SecuRAID114 Disk Array Controller (SCSI)

If SCSI hard disk drives are installed, the disk array controller (SCSI) can be connected to the server. The internal hard
disk drives can be subject to the disk array configuration. The supported RAID configuration includes RAID0 (striping),
RAID1 (mirroring), and RAID5 (striping + parity). Hard disk drives having a different interface cannot be installed
together. In addition, the disk array controller cannot be connected to disk expansion unit.
The SCSI hard disk drives can be hot-swapped by using the optional Hot-swap SCSI HDD cage (3 drives).
IMPORTANT:
cannot contain any hard disk drive.
RAID0 (striping)
Stores data on two hard disk drives by dividing it (striping). Both hard disk drives can be accessed at the same
time. This improves disk access performance compared with using a single hard disk.
IMPORTANT:
RAID0 does not have data redundancy. When a hard disk drive failure occurs, data
cannot be restored.
Logical capacity of the array becomes a multiple of the connected hard disk drive.
RAID1 (mirroring)
Stores the data being saved to one hard disk dive to another hard disk drive. This method is called
"mirroring." When storing data onto one hard disk drive, the same data is simultaneously stored onto another
hard disk drive. When a hard disk drive becomes faulty, the one with the same data can be used. This provides
operation without the system going down.
IMPORTANT:
RAID1 reads or writes data to/from the two hard disk drives at the same time. The disk
access performance is lower than the single disk.
Logical capacity of the array is equal to one hard disk drive connected.
RAID5 (striping + parity)
Stores data onto four hard disk drives by dividing it (striping) in the same way as RAID0. With RAID5, parity
(redundant data) is also divided and stored on four hard disk drives.
Even if one of the configured hard disk drives becomes faulty, data can be used without any problem.
IMPORTANT:
Because data is read from or written to four hard disk drives concurrently, the disk
access performance is lower than that of the configuration using only a single disk.
Because the parity data is saved, the logical capacity is a little lower than the total
capacity of the four hard disk drives.
To build a disk array, at least two hard disk drives are required. Use the SCSI cables sold separately for the connection.
In the figure below, the number of connectors varies depending on the type of the SCSI cable.
If the optional Hot-swap SCSI HDD cage is used, the 3.5-inch device bay
Internal Cabling Diagrams 10-5

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