Disk Array Configuration - Megaraid Configuration Utility; Notes On Using - NEC Express5800 140Rd-4 User Manual

DISK ARRAY CONFIGURATION
– MegaRAID Configuration Utility –
MegaRAID Configuration Utility is a software application to configure the built-in hard disk drives in disk array configuration
by using the onboard disk array controller.

Notes on Using

Note the followings to correctly configure the disk array:
There are different levels of recording RAID. This system supports RAID0, RAID1 and RAID5.
– RAID 0
Stores data on hard disks by dividing it (striping.)
Striping is a technology to store data on disks according to some rules.
Data is divided to be stored on multiple hard disks.
In the figure below, the data is divided into Stripe1 (Disk1), Stripe2 (Disk2), Stripe3 (Disk3) ... and stored on
disks.
All hard disks can be accessed at the same time. This improves disk access performance compared with using a
single hard disk.
IMPORTANT:
cannot be restored.
– RAID 1
Stores the data being saved to one hard disk to another hard disk.
This method is called "mirroring." When storing data onto one hard disk, the same data is simultaneously stored
onto another hard disk. When a hard disk becomes faulty, the one with the same data can be used.
This provides operation without the system going down.
– RAID 5
Stores data onto hard disks by dividing it (striping) in the same way as RAID0. With RAID5, parity (redundant
data) is also divided and stored on multiple hard disks. This is called "distributed parity."
Distributed parity uses one section of a line divided with the set stripe size on hard disks in order.
Data is saved in the order of Stripe1, Stripe2, created parity. Disk space allocated as a parity section is the same
as one hard disk within the RAID5 configuration.
Even if one of the configured hard disks becomes faulty, data can be used without any problem.
When you have configured or changed the disk array configuration, make a backup copy of the configuration
information. You can use the Power Console Plus to make a backup copy. See the online document "Power Console
Plus User's Guide" stored in the EXPRESSBUILDER CD-ROM.
Check the consistency of disk array system on a regular basis.
Consistency check is available for RAID5 or RAID1 only. Use one of the following three methods to check
consistency.
– Check by using this utility (described later in this section).
– Perform scheduled task from the command prompt after operating system start-up. (Refer to the online document
"Power Console Plus User's Guide" stored in the EXPRESSBUILDER CD-ROM or the manual that comes with
the option board.)
– Check by using the Power Console Plus. (Refer to the online document "Power Console Plus User's Guide" stored
in the EXPRESSBUILDER CD-ROM.)
You can use the Power Console Plus to rebuild the failed hard disk drive as well as this utility. (Refer to the online
document "Power Console Plus User's Guide" stored in the EXPRESSBUILDER CD-ROM.)
If a hard disk drive is specified as the standby disk, the data in the failed hard disk drive can be automatically
recovered by using the auto rebuild feature. The hard disk drive to be used as a standby disk must have the same
RAID0 does not have data redundancy. When hard disk failure occurs, data
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