NEC Express 5800/120Lg, Service Manual, Page: 111 / 204

Disassembly and Reassembly 4-45
RAID Controller Board
The functions of a disk array controller are described in the following table.
Functions of a Disk Array Controller
Function Description
Level Support RAID levels RAID0, RAID1, RAID5, and RAID0+1.
Hot plug
Allows a hard disk to be replaced while the system is running depending on
RAID level and system configuration.
Auto rebuild
After the defected hard disk is replaced with a new one, the data saved in the
defected hard disk is automatically recovered from the data saved in the
remaining hard disks depending on RAID level.
Expand capacity The addition of a hard disk without system interruption can automatically
expand the area in which disk arrays are available.
Please note the following when installing and configuring a disk array:
!
Disk array controller boards are easily affected by static electricity.
Handle the disk array controller board only after making body contact
with the metallic frame section of the server chassis in order to discharge
the static electricity from your body. Also, never make contact with
terminals and components on the disk array controller board using your
bare hands.
!
To change the disk array configuration or the RAID level, the hard disks
must be initialized. If important data is saved on the hard disks used to
constitute a disk array, first back up the data on the other hard disks and
then install the boards and configure the disk array.
!
More than one hard disk is required to configure a disk array.
!
Hard disks used in the disk array configuration should have the same
disk revolution rate and capacity.
!
See PCI Board in this chapter for the slots in which a RAID Controller
can be installed.
!
Up to four disk array controller boards can be installed in your server.
!
Several RAID (Redundant Arrays of Independent Disks) levels can be
set for the newly installed disk array controller boards. For details of the
available RAID types, data transfer rate, and array configurations refer to
the online documentation on the
EXPRESSBUILDER CD-ROM that
comes with your system or the vendor documentation that comes with
the disk array controller.
!
The available capacity of the hard disks in the disk array configuration
will be lower than the capacity of the hard disks in a standard
configuration, but the disk reliability is much improved.