In an ActiveCluster uniform configuration, a host must have paths to a volume on both FlashArrays. The scenario describes a single volume losing connectivity while others in the same pod remain accessible. This points to a pathing issue specific to that host-volume relationship. Improper Fibre Channel (FC) zoning or iSCSI network configuration for the host to one of the arrays is the most common root cause for this. When the failover occurred, the volume's I/O was directed to the array to which the host had no properly configured paths, causing the outage for that specific volume.

A. This is a symptom, not the root cause. The lack of uniform access is the result of the improper zoning or network configuration described in option B.

C. If host initiators were not registered, the host would be unable to see any volumes from the array, which contradicts the scenario where other volumes remained available.

1. Pure Storage, "FlashArray Best Practices for VMware vSphere," (2023). In the ActiveCluster section, it states: "The most common cause of a non-uniform presentation is improper zoning or iSCSI configuration... For a datastore to be uniform, it must be presented from both FlashArrays to the ESXi host." (Section: ActiveCluster Best Practices, Subsection: Uniform vs. Non-uniform Storage Access).

2. Pure Storage, "Purity//FA ActiveCluster," Technical White Paper, (2022). This document details the requirement for hosts to have symmetrical SAN connectivity to both arrays in the cluster for uniform access and transparent failover. (Section: Host and SAN Connectivity).