NEC Disk Array Controller N8103-89 - Manual (Page 90)

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1-3. Logical Drive
A logical drive is configured with a group of more than one HDD. It is recognized as a
physical drive by OS. Up to eight logical drives are permitted by the card when four HDDs
are installed in the server.
The figure below shows a sample configuration in which the disk array controller is
connected with four HDDs, three of which create a logical drive and the remaining HDD is
set to a single hot-spare disk.
LD x-x : HDDs assigned to
logical drive
Spare : Hot-spare disk
Spare
LD 1-3
LD 1-1
LD 1-2
Disk array controller
Logical drive 1
Channel 1
(Port 1)
Channel 3
(Port 3)
Channel 2
(Port 2)
Channel 4
(Port 4)
1-4. Parity
The parity means redundant data. A single set of redundant data is created from the data
saved in more than one HDD.
The created redundant data is used for data recovery when a HDD is defected.
1-5. Hot-Swap
The hot-swap enables a HDD to be removed (replaced) under system operation.
Check
For the hot-swap with the card, an additional HDD cage must be connected
to the card.