By default, DMP uses the Minimum Queue I/O policy for load balancing across paths for all array types. Load balancing maximizes I/O throughput by using the total bandwidth of all available paths. I/O is sent down the path that has the minimum outstanding I/Os.

For Active/Passive (A/P) disk arrays, I/O is sent down the primary paths. If all of the primary paths fail, I/O is switched over to the available secondary paths. As the continuous transfer of ownership of LUNs from one controller to another results in severe I/O slowdown, load balancing across primary and secondary paths is not performed for A/P disk arrays unless they support concurrent I/O.

For other arrays, load balancing is performed across all the currently active paths.

You can change the I/O policy for the paths to an enclosure or disk array. This operation is an online operation that does not impact the server or require any downtime.