During the planning phase, the most critical prerequisite is to ensure all components of the proposed solution are compatible. This involves using the NetApp Interoperability Matrix Tool (IMT) to verify that the ONTAP version, controller models, I/O modules, switch models and firmware, and any other hardware are mutually supported for a MetroCluster configuration. This step prevents deployment failures and ensures the final system is supported by NetApp.

B. Disabling storage failover is a procedural step during the installation or a maintenance window, not a prerequisite in the planning phase.

C. Removing cluster nodes is a destructive action and is contrary to the goal of building a high-availability solution during planning.

D. Disabling RAID protection is never a standard prerequisite; RAID is a fundamental data protection feature of ONTAP systems.

1. NetApp. (2023). MetroCluster Installation and Configuration Guide for ONTAP 9.13.1. NetApp Documentation. Section: "Pre-installation requirements," subsection "Supported configurations." This section emphasizes verifying all components using the NetApp Interoperability Matrix Tool (IMT).

2. NetApp Interoperability Matrix Tool (IMT). (https://imt.netapp.com/). This official tool is the primary source for verifying compatibility of all hardware and software components for any NetApp solution, including MetroCluster.