9-44 Upgrading Your ServerUse of a disk expansion unit in a disk array configurationA disk expansion unit is an exclusive device that can install up to 14 hard disk drives. (The numberof hard disk drives depends on the model.) The server containing a disk array controller board canconnect one or two of these devices. For details on the number of devices connected, see themanuals provided with the disk array controller and disk expansion unit.IMPORTANT: A disk expansion unit is provided with no hard diskdrives. You need to purchase hard disk drives separately.An optional cable may be required to connect with a disk expansion unit. Refer to the manualcoming with the disk expansion unit for details.After connecting the disk expansion unit, use the RAID configuration utility in the chip on the boardto set the disk expansion unit in a disk array configuration (RAID0, RAID1, or RAID5). (The utilityvaries depending on the board.) For details on settings and the setting methods, see the onlinedocument in the NEC EXPRESSBUILDER CD-ROM provided with the server or the manualprovided with the board.While a disk expansion unit is set in a disk array configuration, you can use the "Auto Rebuild"feature of the disk array controller to restore data if one of the hard disk drives installed in the diskexpansion unit fails. (Replace the failing hard disk drive while the power is on. (Hot swapping))
