MPDEV_POLLER enables polling of the paths to multipath set members
    when set to ON (1). Polling allows early detection of errors on
    inactive paths. If a path becomes unavailable or returns to
    service, the system manager is notified with an OPCOM message.
    When set to OFF (0), multipath polling is disabled. The default is
    ON. Note that this parameter must be set to ON to use the
    automatic failback feature.