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5 PS Series Architecture: MPIO with Devices That Have Unequal Link Speeds | TR1105 v1
1 Best Practice for network interfaces in a PS Series SANs
A Best Practice when deploying hosts and storage arrays on the same PS Series SAN is to utilize a common
network speed throughout the environment. This includes host ports (NIC, offload cards or HBAs),
network switching, and PS Series arrays. For example, to obtain the best results install 1GB components in
a configuration using a 1Gb array (such as a PS6100) and 10Gb switches and host interfaces when using
10Gb capable arrays (such as the PS6210). When this is not possible, the PS Series MPIO software included
in the Windows, VMware and Linux host tools attempts to optimize the environment for performance
within the limits imposed by mismatched speeds.
1.1 Distribution of data in a PS Series SAN
Data in a PS Series SAN is automatically distributed across multiple members in a pool. Each of these
members contains resources to service the IT workload, including disks, cache and I/O ports. This
distribution of resources permits the PS Series SAN to scale up or down easily by simply adding or
removing member arrays to the group. When used with non-enhanced MPIO, the PS Series Group
automatically forwards the I/O traffic to the appropriate member if the request is received by another
member. When using the PS Series MPIO extensions, this forwarding is not needed since there are
connections made from the host to each member that holds a portion of the data.