3. Understanding RAID
page 20
LaCie Biggest F800
User’s Manual
RAID 5 + Hot Spare
This level is the same as RAID 5, but one disk is designated
as a “Hot Spare,” which means that in the event of a disk
failure, the “Hot Spare” disk would automatically be activated
to replace the failed disk.
The storage capacity of a RAID 5+ Hot Spare array follows
the same logic as that of RAID 5, but with the difference
being that there is one less disk in the array. So, for instance,
if there was a RAID 5+ Hot Spare array with three drives of
varying capacities of 40GB, 50GB and 60GB, and one disk
designated as the hot spare with a capacity of 70GB, the
total capacity of the array would be 80GB [2 (3 disks – 1
disk) x 40 = 80].
E
D
C
B
A
CONTROLLER
A
C
P
EF
G
B
H
P
CD
E
F
P
AB
P
GH
D
H
O
T
S
P
A
R
E
This diagram represents a
RAID 5 + Hot Spare array,
consisting of four disks, which
are connected to the
Controller. Parity blocks are
represented by the letter P.
