IBM XIV Gen3 Series, Planning Manual

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Redundant configuration with 12 paths to each volume
Figure 14 on page 57 illustrates a redundant configuration in which all six interface
modules are accessed by using 12 paths per LUN on the host. This configuration is
ideal for benchmarking and higher performance host systems with the highest I/O
requirements.
In this configuration:
v Each host is equipped with dual HBAs. Each HBA (or HBA port) is connected to
one of two Fibre Channel switches.
v Each Fibre Channel switch has a connection to a separate Fibre Channel port on
each of the six interface modules.
v Each volume can be accessed through 12 paths. Twelve paths is the maximum
number of paths to consider. There is no benefit to having more than 12 paths.
Using more than 12 paths might cause issues with host processor usages and
server reliability if a path failure occurs (such as a host HBA failure).
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Module 9
Module 8
Module 7
Module 6
Module 5
Module 4
Hosts
Switch B
Switch A
Figure 13. Fully redundant Fibre Channel configuration with six paths to each volume
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IBM XIV Gen3 281x-11x, 281x-21x, and 281x-314 Planning Guide