NEC Express 5800/120Lg, Service Manual, Page: 63 / 204

Configuring Your System 3-21
Configuring the RAID Controller
RAID (Redundant Array of Independent Devices) options are available for your
system, providing added security and high availability.
If you order a system with a RAID controller, the system is pre-configured at
the factory according to Table 3-2 below.
Table 3-2. RAID Configurations
Number of
Hard Drives RAID Level
Configured Hard Drives in
Array
Description
1 7 1
JBOD (RAID 7) Known as Just a Bunch of Drives ,
JBOD allows the controller to access the drives
independently. This configuration has no redundancy
and does not use striping.
2 1 2 Mirroring (RAID 1) Drives are paired and mirrored.
All data is 100% duplicated on an equivalent drive
(fully redundant).
3 5 3 Striping with Parity (RAID 5) Data is striped across
several physical drives. Parity protection is used for
data redundancy.
4 or more 5 4 (one standby
drive) Striping with Parity (RAID 5) with a standby drive
The array consists of three ON-LINE drives and one
STANDBY drive. The standby replacement drive, or
hot spare, is one of the most important features RAID
provides to achieve automatic, non-stop service with a
high degree of fault-tolerance.
If you want to change the RAID level or add additional hard disks to the array,
use the RAID configuration utility. The RAID configuration utility is included
with the RAID controller.
If you are adding the RAID controller to an existing system, the RAID
configuration utility allows you to configure your disk array before reinstalling
your network operating system. The RAID controllers support various versions
of RAID technology (referred to as RAID levels). To use any RAID level, you
must configure the RAID controller using the RAID configuration utility prior
to installing your Network Operating System. For an explanation of this utility,
refer to the documentation that was shipped with the RAID controller. It
describes RAID technology and provides tips on making your array perform
well in your specific application. It also
covers array hardware preparation,
configuration, and initialization. After completing the steps in the manual, you
can install your Network Operating System.
If you want to remotely configure the array (from a PC client); increase array
capacity online; or monitor statistics on disk and controller activity, you must
install the array manager provided with your RAID subsystem. Increasing array
capacity is covered in the user's guide shipped with the option.