Hot Spares; Figure 2-4. Example Of Parity - Dell PowerEdge Expandable RAID Controller 3 User Manual

F i g u r e 2 - 4 . E x a m p l e o f P a r i t y
Parity
Generator

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.
PERC 3 implements automatic and transparent rebuilds using hot spare
drives, providing a high degree of fault tolerance and zero downtime. The
PERC 3 RAID management software allows you to specify physical drives as
hot spares. When a hot spare is needed, PERC 3 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.
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I n tr o d uc t io n t o RA I D