RAID 5 + Spare
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Intel® Entry Storage System SS4000-E User Guide
Figure 41. RAID 5 - Data Striping with Striped Parity
In a RAID 5 + spare configuration, three of the disks use RAID 5, and the fourth is empty.
If any of the three disks fails, it is immediately rebuilt using the fourth spare disk. As a
result, you can remove the failed disk and still have the ongoing fast performance and data
protection offered by RAID 5. When the failed disk is repaired or replaced and re-installed
into the storage system, it automatically becomes the spare for the other functioning three.
You can use RAID 5 + spare only if your storage system has four disks. If the disks are not
the same size, the smallest of the disks determines how much disk space is available for
data, similar to RAID 5.
Figure 42. RAID 5 + Spare
D1
D2
P1
P2
D3
D4
Disk 1
Disk 2
Disk 3
AF000289
P1
D1
D2
D3
P2
D4
Disk 1
Disk 2
Disk 3
Spare
AF000291
Levels of RAID
171