NEC 140He, User Manual

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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 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.
Where is the figure?All hard disks 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 hard disk failure occurs,
data cannot be restored.
– RAID 1
Stores the data being saved to one hard disk drive 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.
– RAID 5
Stores data onto hard disk drives 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 following order: 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