144
Summary of the RAID 5 function (Redundant
Arrays for Independent Disks, independent
data disks with distributed parity blocks)
It is possible to use the RAID 5 function with an optional
extension unit.
RAID level 5 regards 3 or more drives as one drive, and it is
possible to read data by attaching error correction data
even though one of the drives is broken automatically. (It is
impossible to recover data if two drives are simultaneously
damaged or the second drive fails during the data recovery
process.)
RAID level 5 requires a minimum of 3 drives to implement.
When using the RAID function, the logical disk size of the
extension unit will be as below.
Logical disk size = Smallest size of the disk among the
disks in the extension unit x (Number of the disks in the
extension unit - 1)
Note:
Depending on the model of a hard disk drive, the
logical disk size may be a few percent smaller than the
size resulting from the formula above.
Important:
• When connecting two extension units or more with this
unit, it is impossible to connect the extension unit with
the RAID 5 function and the one without the RAID 5
function at the same time.
• When the RAID 5 function is used, it is impossible to
use two hard disks in this unit. The recorded pictures in
those disks will not be deleted.
■
RAID 5 Function of the Extension Unit
●
Setup/cancel the RAID 5 function
Do the following to set or cancel the RAID 5 function with an
optional extension unit.
Refer to the operating instructions of the extension unit for
further information.
z
Make sure that the power of this unit and all of the
extension units to be connected is OFF.
x
To set the RAID 5 function, set the mode switch of the
extension unit to "RAID 5".
To cancel the RAID 5 function, set the mode switch of
the extension unit to "SINGLE".
c
Make sure that the HDD POWER switch of the extension
unit is "ON".
v
Turn the power of the extension unit on.
b
Turn the power of this unit on.
→
The "HDD DISK MENU" will be displayed automati-
cally after the system check when the hard disk
configuration has been changed such as when an
extension unit is newly connected.
Important:
• When the RAID 5 function is set or canceled, all data on
each hard disk of the extension unit will be deleted.
• When turning the power on, turn on the power of the
extension unit first, and then turn the power of this unit
on. Otherwise, the extension unit may not work correct-
ly.
