4-30 Configuring Your ServerRAID CONFIGURATIONThis section describes how to configure the internal hard disk drives as the disk array drive by usingthe onboard RAID controller. Refer to the manual of the optional disk array controller for how toconfigure the hard disk drives by using the optional disk array controller.To use the hard disk drives installed in the disk expansion unit in a disk array, the optional disk arraycontroller is necessary. Refer to the manual of the optional disk array controller or disk expansionunit for details.Onboard RAID FeaturesYou can configure a disk array (RAID0, RAID1, or RAID10) by using the onboard RAID controllerof the server. RAID0 (striping)Stores data on two, three, or four hard disk drives by dividing it (striping). All the harddisk drives can be accessed at the same time. This improves disk access performancecompared with using a single hard disk drive.IMPORTANT: RAID0 does not have data redundancy. When a hard disk drivefailure occurs, data cannot be restored. Logical capacity of the array becomes a multiple of the connectedhard disk drive. RAID1 (mirroring)Stores the data being saved to one hard disk dive to another hard disk drive. This methodis called "mirroring." When storing data onto one hard disk drive, the same data issimultaneously stored onto another hard disk drive. When a hard disk drive becomesfaulty, the one with the same data can be used. This provides operation without the systemgoing down.IMPORTANT: RAID1 reads or writes data to/from the several hard disk drives atthe same time. The disk access performance is lower than the singledisk. Logical capacity of the array is equal to one hard disk driveconnected.