NEC Server 140Rc-4 - Manual (Page 295)

Upgrading Your Server 9-9
7. Power on the server to check to see that the disk lamp on the front of the hard disk drive
goes on (green).
IMPORTANT: If a hard disk is added to the server operating in
RAID1 by using the expand array feature, the RAID is automatically
changed to RAID0+1. (However, it is not possible to set RAID0+1
directly by using a specific utility.)
Removal
Remove the hard disk in reverse order of the installation steps 1 to 3. To use the server with the hard
disk removed, insert a dummy tray into the empty slot.
NOTE: If removing a failing hard disk drive, confirm the slot in which
the DISK lamp of the hard disk drive is amber before starting the
removal.
DISK lamps