HP D2D100 Backup System - Manual (Page 114)

Look at the RAID & Disks page for more information.
The disk status icon in the Physical Disks section indicates an error condition. Note also the message
in the RAID Status section that warns that “RAID is still operational but failed disk should be replaced
as soon as possible”.
If more than one disk fails
You will lose all data on the HP D2D Backup System and the message in the RAID Status section warns
that there are “Too few disks to operate”. However, the device operating system is not stored on any
of the disks, so the HP D2D Backup System is still usable after replacing the failed disks. Use the Web
114 Hard disk replacement