Multiple paths to an array LUN can be used to distribute load

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I/O requests for a given LUN can be distributed over all the available optimized paths to the LUN. This is unlike in previous releases, where in spite of multiple paths being available, I/O requests for a given LUN were sent over a single active optimized path only.

Distribution of I/O requests for a given LUN over multiple paths results in the following benefits:

  • Improved efficiency due to maximum utilization of all available and optimized paths

  • Improved performance due to load balancing over multiple paths

For example, on an active-active array, I/O requests for a given LUN can be distributed over all the four target ports available for that LUN. For an asymmetric active-active array LUN, I/O requests can be distributed over all the optimized paths for a given LUN.

Commands to view load balancing over multiple paths for a given LUN

You can run the following commands to view the distribution of load for a given LUN across multiple paths:

  • storage disk show -disk <LUN name> displays the distribution of I/O load across the available paths for a given array LUN.

  • storage path show-by-initiator -array-name <array name> displays the distribution of I/O load across all the initiator ports on the ONTAP system that is connected to a given storage array.

  • storage path show -by-target -array-name <array name> displays the distribution of I/O load across all the target ports on a given storage array.