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RAID 5 + HotSpare
In the RAID 5 + HotSpare mode, also called HotStand, the last disk in the system
is left empty as backup. When any of the disks in the system fails, the back up
disk will automatically be rebuilt to replace the failure disk. RAID 5+HotSpare
mode provides more than decent data protection and fault tolerance. The speed
of operation is slow in comparison to other RAID modes.
Under the RAID 5+HotSpare mode, 4 HDDs in an array are required. The
storage capacity will become 3 minus 1, totaling only 2 HDD storing capacity.
But it is limited to the smallest size of HDDs, plus 1 more HDD as the backup
disk.
RAID 5+HotSpare
Disk 1
Disk 2
Disk 3
Disk 4
A1
A2
B1
Bp
Cp
C1
D2
Dp
Ap
B2
C2
D1
Spare
If one of the disks fails, the source data can be reconstructed through parity
calculation without replacing it with a new disk. In the 4-Bay RAID System, the
"Disk 4" is located in the "HDD 1" slot position.
Summary of Contents for DM4
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