Adaptec 2020SA User Guide - Page 147

RAID10, This dual-level RAID type is created by using two or more equal

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About RAID Using parity minimizes the storage cost of redundancy. Because only one drive is used to store parity, a three-drive array, which is the worst case, uses only one-third of the total capacity for redundancy. In larger arrays, the storage cost of redundancy decreases proportionately RAID 5 write performance is limited by the need to generate parity data for every write. Read performance is good because the load is spread equally across all the drives. RAID 10 This dual-level RAID type is created by using two or more equalsized RAID 1 arrays to create a RAID 0. Both read and write performance are improved due to array striping. However, the performance improvement costs additional storage space due to the mirroring of the arrays. RAID 10 RAID 1 Data 0 Data 2 Data 4 Data 6 Top-Level Arrays RAID 1 Data 1 Data 3 Data 5 Data 7 Drive Data 0 Data 2 Data 4 Data 6 Drive Data 0 Data 2 Data 4 Data 6 Second-Level Arrays Drive Data 1 Data 3 Data 5 Data 7 Drive Data 1 Data 3 Data 5 Data 7 E-4

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E-4
About RAID
Using parity minimizes the storage cost of redundancy. Because
only one drive is used to store parity, a three-drive array, which is
the worst case, uses only one-third of the total capacity for
redundancy. In larger arrays, the storage cost of redundancy
decreases proportionately
RAID 5 write performance is limited by the need to generate parity
data for every write. Read performance is good because the load is
spread equally across all the drives.
RAID 10
This dual-level RAID type is created by using two or more equal-
sized RAID 1 arrays to create a RAID 0. Both read and write
performance are improved due to array striping. However, the
performance improvement costs additional storage space due to
the mirroring of the arrays.
Drive
RAID 1
RAID 1
Top-Level Arrays
Second-Level Arrays
Data 2
Data 4
Data 6
RAID 10
Data 2
Data 4
Data 6
Data 0
Data 2
Data 4
Data 6
Data 0
Data 3
Data 5
Data 7
Data 1
Data 3
Data 5
Data 7
Data 1
Data 3
Data 5
Data 7
Data 1
Drive
Drive
Drive
Data 0