NetApp ONTAP systems require a Fibre Channel (FC) switched fabric for SAN connectivity. The ONTAP FC target ports are designed to perform a Fabric Login (FLOGI) to an FPort on an FC switch to join the fabric. A direct connection between a host's NPort and an ONTAP target's NPort is not a supported topology. Without a switch, the necessary fabric services (like the Simple Name Server) are unavailable, which prevents the host initiator from discovering the ONTAP target ports and the LUNs mapped to them. Therefore, the LUN is not visible because the required FC switch is missing from the configuration.

A. Multipathing must be used and connected to another FC path.

Multipathing provides high availability and performance; it is not a prerequisite for initial LUN discovery over a single, valid path.

B. NPV must be enabled on the host before trying to attach to the LUN.

NPort Virtualization (NPV) is a feature enabled on an FC switch, not on a host, to reduce the number of domain IDs in a fabric.

C. NPIV must be enabled on the host before trying to attach to the LUN.

NPort ID Virtualization (NPIV) allows a single physical HBA port to register multiple WWPNs, which is primarily for virtualized environments and not required for a basic connection.

1. NetApp ONTAP SAN Configuration Guide (ONTAP 9.11.1): In the section "Overview of SAN

" the architecture consistently depicts hosts and storage systems connected through one or more FC switches. The guide states

"A SAN is a dedicated network that connects servers (hosts) and storage systems. The components of a SAN include HBAs in the hosts

switches

cables

and storage systems." This implies a switch is a fundamental component. The absence of any documented support for direct-attach FC topology confirms it is not a valid configuration.

Source: NetApp ONTAP Documentation Center

"SAN configuration overview

" Published: 2023-05-12.

2. NetApp Technical Report 4080 (TR-4080): Fibre Channel SAN Configuration Guide: This document details the components of a supported FC SAN. The "Fibre Channel SAN components" section explicitly lists "Fibre Channel switches" as a core component alongside host bus adapters and storage systems. It does not describe or validate a direct-connect topology.

Source: NetApp TR-4080

Page 8

Section 2.1 "Fibre Channel SAN components."

3. Brocade Fabric OS Administration Guide: While not a NetApp document

it is an industry-standard reference for FC fabrics. It defines the port types and login processes (FLOGI

PLOGI) that underpin FC SANs. It clarifies that NPorts (hosts

storage) log in to FPorts (switches) to form a fabric

a process that cannot occur in a direct NPort-to-NPort connection without special considerations not supported by ONTAP for its primary SAN function.

Source: Brocade Fabric OS Administration Guide

9.0.x

Section on "Fabric Principles" and "Port Types."