Virtual Disk - NEC Express5800 User Manual

Virtual Disk

Virtual disk is a logical drive defined in disk group. It is recognized as a physical drive by OS. The
allowable number of virtual disks is up to 16 per disk group, or up to 64 per controller.
The figure below shows a sample configuration in which the Onboard RAID Controller (LSI
Embedded MegaRAID) or Optional RAID Controller is connected with three hard disk drives,
creating one Disk Group. Two RAID0 virtual disks (VD) are defined in the Disk Group.
VD0-1
20GB
VD1-1
16 GB
HDD 1
(36 GB)
Parity
The parity means redundant data. A single set of redundant data is created from the data saved in
more than one hard disk drive.
The created redundant data is used for data recovery when a hard disk drive is defected.
Hot-Swap
The hot-swap enables a hard disk drive to be removed (or replaced) under system operation.
Hot-Spare
The hot-spare is prepared as an auxiliary hard disk drive substituting for a defected hard disk drive
included in a logical drive which is configured at a redundant RAID level. Detecting a hard disk
drive fault, the system disconnects the hard disk drive (or makes it offline) and starts rebuild using
the hot-spare.
RAID Controller
VD0-2
20GB
VD1-2
16 GB
HDD 2
(36 GB)
Configuring Your Server 4-39
DG0 108 GB
VD0 (RAID0)
VD0-3
60 GB
20GB
VD1-3
VD1 (RAID0)
16 GB
48 GB
HDD 3
(36 GB)