The correct installation sequence for an Avaya IX™ Messaging High Availability (HA) solution is critical for a successful deployment. The process begins with installing the WebLM server, which manages the necessary licenses for all other components. Next, the Primary Application Server is installed, establishing the initial configuration and database. Following this, the Consolidated Server, which provides centralized storage for the HA pair, is deployed. Finally, all Secondary Application Servers are installed. This order ensures that the primary system and its dedicated storage are operational before the redundant servers are added to the cluster.

A: The WebLM server is a prerequisite and must be installed first to provide licenses; it cannot be installed after the Primary Server.

B: According to the official Avaya deployment procedure, the Primary Application Server is installed before the Consolidated (storage) Server.

D: The Consolidated Server provides essential shared storage for the HA cluster and must be installed and configured before the Secondary servers.

1. Avaya Aura® Messaging Documentation Library, "Deploying Avaya Aura® Messaging", Release 10.1, February 2020.

Reference: Chapter 4: High Availability solution deployment, Section: "High Availability solution deployment workflow". This section explicitly outlines the installation order as: 1. Deploy WebLM server, 2. Deploy the first Application Server (Primary), 3. Deploy the Storage Server (Consolidated), 4. Deploy the second Application Server (Secondary). This directly supports option C.

2. Avaya Learning, "Avaya Aura® Messaging Implementation and Maintenance (71800X) Courseware".

Reference: Module on "High Availability Installation". The course materials detail the step-by-step process for deploying an HA environment, which specifies that the Primary Application server is installed after WebLM but before the Consolidated Storage server, which in turn must be installed before any Secondary servers.