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Decreasing mapped LUN paths with SLM for LUNs created prior to Data ONTAP 8.3

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.

Before you begin

Your Storage Virtual Machine (SVM) must be configured with at least one SAN LIF on the desired protocol on the node owning the LUN and node's HA partner.

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.

About this task

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.

Steps

  1. Limit the nodes with paths to the LUN to the node owning the LUN and the owning node's HA patner: lun mapping add-reporting-nodes -vserver vserver_name -path lun_path -igroup igroup_name -local-nodes
  2. Verify that the LUN has been removed from the existing LUN map: lun mapping show -fields reporting-nodes
  3. Rescan the host as appropriate for the client operating system to verify that the LUN is mapped only to its owning node and HA partner node.