A new attribute, cam_ccfg_aa_enable, has been added to the cam subsystem to control preferred path usage.
When enabled, this attribute utilizes the target port group information from the storage controller to determine the optimal paths and use these optimal paths for I/O access. When disabled, all paths to that device are used.
Active-active asymmetric storage controllers may incur a performance penalty when accessed on non-optimal paths.
For more information, including setting this attribute, see the revised sys_attrs_cam(5) reference page delivered in this kit.