NEC N8103-89 manual Logical Drive, Parity, Hot-Swap

70

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.

Disk array controller

Channel 1

(Port 1)

Channel 2

(Port 2)

Channel 3

(Port 3)

Channel 4

(Port 4)

Logical drive 1

LD 1-1

LD 1-2

LD 1-3

Spare

LD x-x : HDDs assigned to logical drive

Spare : Hot-spare disk

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.

For the hot-swap with the card, an additional HDD cage must be connected to the card.

Check