The MPIO Policy defines how the host distributes IOs across the available paths to the storage. The Round Robin (RR) policy distributes IOs evenly across all Active/Optimized paths. A newer MPIO policy, least_cmd_load, is similar to round robin in that IOs are distributed across all available Active/Optimized paths, however, it provides some additional benefits. The least_cmd_load policy will bias IOs towards paths that are servicing IO quicker (paths with shorter queues). In the event that one path becomes intermittently disruptive or is experiencing higher latency, least_cmd_load will prevent the utilization of that path reducing the effect of the problem path.
We recommend using "least_cmd_load".
scsimgr set_attr -D _rdiskX_ -a load_bal_policy=least_cmd_load