On a two-node NetApp AFF ASA cluster, what is the recommended minimum number of paths for a SAN environment from the client host perspective?

For a two-node NetApp AFF ASA cluster, the recommended minimum configuration for a highly available SAN environment includes redundancy at every level. This typically involves two Host Bus Adapters (HBAs) in the client host, two independent SAN fabric switches, and the two controllers of the ASA cluster. In this standard redundant topology, each HBA connects to a different fabric switch. Each switch is then connected to both nodes in the cluster. This configuration results in two paths to each storage controller, one through each fabric, for a total of four paths from the host perspective. This ensures continued access in the event of a single HBA, cable, switch, or controller failure.

A. 2: Two paths would only provide controller-level redundancy but would lack protection against a host HBA or SAN fabric switch failure, which is not a recommended practice for production environments.

B. 8: Eight paths would provide greater redundancy and performance but is not the minimum recommended number. This typically involves quad-port HBAs or four dual-port HBAs, exceeding the minimum requirement.

D. 16: Sixteen paths represents a very high-performance and highly redundant configuration, which is significantly more than the recommended minimum for a standard deployment.

1. NetApp TR-4080

Fibre Channel SAN Configuration Guide for ONTAP 9.11.1

Page 10

Section 3.1 Host Connectivity.

The document states

"For high availability

NetApp recommends that you use at least two initiator ports on the host and connect them to redundant fabrics." Figure 3 on the same page

"Dual-fabric SAN

" explicitly illustrates a configuration with a dual-HBA host connecting to a two-node cluster through two fabrics

resulting in four distinct paths.

2. NetApp TR-4333

SAN-TRINITY: A NetApp Guide to SAN Architectures

Page 7

Section 2.2 High Availability.

Figure 2

"Fully redundant SAN

" depicts the standard architecture for high availability. The diagram shows a host with two HBAs

two switches

and two storage controllers. Tracing the connections from the host to the HA pair of controllers clearly shows four paths

which is the foundation of a resilient SAN design.

3. NetApp Product Documentation

ONTAP 9 SAN Configuration Guide

"SAN configuration overview" section.

This guide consistently illustrates best-practice SAN configurations. The diagrams for setting up FC or iSCSI for an HA pair show redundant connections from the host

through separate fabrics

to both nodes in the cluster. This standard topology results in four paths to ensure no single point of failure.