Gateway ADAC ULTRA2 S466 - Manual (Page 27)

Chapter 2 Introduction to RAID 13
Hot Spares
A hot spare is an extra, unused disk drive that is part of the
disk subsystem. It is usually in standby mode, ready for
service if a drive fails. Hot spares permit you to replace
failed drives without system shutdown or user intervention.
ADAC Ultra2 S466 implements automatic and transparent
rebuilds using hot spare drives, providing a high degree of
fault tolerance and zero downtime. The ADAC Ultra2
S466 RAID Management software allows you to specify
physical drives as hot spares. When a hot spare is needed,
the ADAC Ultra2 S466 controller assigns the hot spare that
has a capacity closest to and at least as great as that of the
failed drive to take the place of the failed drive.
Important
Hot spares are only employed in arrays with redundancy, for
example, RAID levels 1, 3, 5, 10, 30, and 50.
A hot spare connected to a specific ADAC Ultra2 S466
controller can only be used to rebuild a drive that is
connected to the same controller.