You can reduce the number of paths mapped to your LUNs by using Selective LUN Map (SLM). Reducing the number of LUN paths simplifies host side multipath management and ensures that the number of host paths to the LUN does not exceed the maximum supported by Data ONTAP.
For FC configurations, you must configure two LIFs per node on separate physical ports. For iSCSI configurations, you must configure a single iSCSI LIF on an ifgrp spanning at least two physical ports. This ensures that an active/optimized path to the LUN is maintained in the event of a single port or switch failure.
Beginning with Data ONTAP 8.3, SLM is enabled by default on all new LUN maps. You must manually apply SLM to LUNs created prior to Data ONTAP 8.3 by manually adding the reporting nodes to the LUN map. Adding the reporting nodes limits the number of host paths to the LUN owning node and its HA partner.