B.7
RAID 5EE Arrays
A RAID 5EE array—also known as a hot space—is similar to a RAID 5 array except that it includes a distributed
spare drive and must be built from a minimum of four disk drives.
Unlike a hot spare, a distributed spare is striped evenly across the disk drives with the stored data and
parity data, and can’t be shared with other logical disk drives. A distributed spare improves the speed at
which the array is rebuilt following a disk drive failure.
A RAID 5EE array protects your data and increases read and write speeds. However, capacity is reduced by
two disk drives’ worth of space, which is for parity data and spare data.
In this figure, S represents the distributed spare, P represents the distributed parity data.
Unused Space = 150 GB
Disk Drive 1
Disk Drive 2
Disk Drive 3
Disk Drive 4
250 GB
250 GB
400 GB
400 GB
Drive Segment Size
(Smallest Disk Drive)
Disk Drive 2
Disk Drive 3
Disk Drive 4
Disk Drive 1
Unused Space = 150 GB
Disk Drives in Logical Drive
Based on the drive segment sizes used:
and hot spare
RAID 5EE Logical Drive = 500 GB plus parity
P
1 S
. . .
449
2 P
. . .
S
S 3
. . .
500
P 4
. . .
53
Microsemi Proprietary and Confidential. Installation and User's Guide Revision 5
Understanding RAID
