RAID and Subsystem Architectures RAID Configurations
RAID 1+0 – Mirrored Stripe
Unused space
File 3 File 2 File 1
Reliability Read Performance
Write Performance
Block C1 Block B3 Block B1
Block A5 Block A3 Block A1
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Block A5
Block C1 Block B3 Block B1
Block A3 Block A1
Block C2 Block B4 Block B2
Block A6 Block A4 Block A2
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Block C2 Block B4 Block B2
Block A6 Block A4 Block A2
RAID 1 + 0 (mirrored striping array): Uses pairs of drives to create two copies of each block of data Provides very good fault-tolerance Read performance can be slightly better because drives can cooperate to read different “pieces” of the data Write performance can be slightly degraded because both drives must write a copy of the data Using duplexed controllers with one disk on each controller eliminates write performance hit High cost due to inefficiency in use of disk space (50%)