Load balancing

By default, the DMP uses the Minimum Queue policy for load balancing across paths for Active/Active, A/P-C, A/PF-C and A/PG-C disk arrays. Load balancing maximizes I/O throughput by using the total bandwidth of all available paths. I/O is sent down the path which has the minimum outstanding I/Os.

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

Both paths of an Active/Passive array are not considered to be on different controllers when mirroring across controllers (for example, when creating a volume using vxassist make specified with the mirror=ctlr attribute).

For A/P-C, A/PF-C and A/PG-C arrays, load balancing is performed across all the currently active paths as is done for Active/Active arrays.

You can use the vxdmpadm command to change the I/O policy for the paths to an enclosure or disk array.

More Information

Specifying the I/O policy