RAID and Subsystem Architectures RAID Configurations
RAID 4 – Block Striping
Unused space
Parity data File 3 File 2 File 1
Block B4 Block C1
Block C1 Block B4 Parity
Block A1 Block A4
Reliability Read Performance
Write Performance
Parity
Block C2
Block B1 Block A7
Block B2
Block A2 Block A5 Block A8
Block C2 Block B5
Block B2
Block C3 Block B6 Block B3 Block A9
Block B2 Block B6
Block A3 Block A6
Parity Parity
Block B1
Parity Parity Parity
Parity Parity Parity
RAID 4 (block striping with dedicated parity disk): Data is striped at the block level Parity information is written to dedicated parity disk Read performance is very good because data is spread across all drives Write performance is inhibited by the parity calculation process