NEC BladeServer Express5800 Series User Manual page 87

4-30 Configuring Your Server
Virtual Disk
Virtual disk is a logical drive defined in disk group. It is recognized as a physical drive by OS. Up to
40 virtual disks are permitted by the on-board RAID (LSI Logic MegaRAID SAS PCI
EXPRESS ROMB).
The figure below shows a sample configuration in which the on-board RAID (LSI Logic
MegaRAID SAS PCI EXPRESS ROMB) is connected with three HDDs, creating one disk
group (DG). Two RAID5 virtual disks (VD) are defined in the DG.
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 HDD.
The created redundant data is used for data recovery when a HDD is defected.
Hot-Swap
The hot-swap enables a HDD to be removed (or replaced) under system operation.
Hot-Spare Disk
The hot-spare disk is prepared as an auxiliary HDD substituting for a defected HDD included in a
logical drive which is configured at a redundant RAID level. Detecting a HDD fault, the system
disconnects the defected HDD (or makes it offline) and starts rebuild using the hot-spare disk.
NOTE:
"Features of On-board RAID (LSI Logic MegaRAID SAS PCI
EXPRESS ROMB)".
Disk array controller
VD0-2
20GB
VD1-2
16 GB
HDD 2
(36 GB)
For standby rebuild (rebuild using hot-spare disks), see
DG0 108 GB
VD0 (RAID5)
VD0-3
40 GB
20GB
VD1-3
VD1 (RAID5)
16 GB
32 GB
HDD 3
(36 GB)