Write Patterns And Parity In Network Raid-5 (Single Parity) - HP StorageWorks P4000 User Manual

1. Parity for data blocks A, B, C
2. Parity for data blocks D, E, F
3. Parity for data blocks G, H, I
4. Parity for data blocks J, K, L
Figure 72 Write patterns and parity in Network RAID-5 (Single Parity)
.
Network RAID-6 (Dual Parity)
Network RAID-6 divides the data into stripes. Each stripe is stored on four of the storage systems in
the cluster, and parity is stored on a fifth and sixth system. Data in a volume configured with Network
RAID-6 is available and preserved in the event that any two storage systems become unavailable.
Network RAID-6 volumes are configured as thin provisioned by default. Network RAID-6 also requires
a snapshot schedule. When a new Network RAID-6 volume is created, a basic snapshot schedule is
also created. If an existing volume is converted to Network RAID-6, if that volume does not have a
snapshot schedule, a basic schedule is created when the volume is converted. This basic snapshot
schedule can be edited to fit the needs of the volume.
Best applications for using Network RAID-6 volumes include applications with mostly read, sequential
workloads on larger clusters, such as file shares and archiving.
Figure 73 illustrates the write patterns on a cluster with six storage systems configured for Network
RAID-6.
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