Guidelines for OpenVMS Cluster Configurations

This document, "Guidelines for OpenVMS Cluster Configurations" (April 2001, by Compaq), is a comprehensive guide for designing and optimizing OpenVMS Cluster systems. Its primary purpose is to help users maximize benefits in availability, scalability, performance, and ease of system management.

The guide covers the following key areas:

1. System Design Foundations: It begins by outlining crucial business and application requirements, such as budget, availability levels (conventional, 24x365, disaster-tolerant), scalability needs for future growth, physical location, and security. It also discusses balancing processor, memory, and I/O resources.
2. Hardware Components: It details the various hardware elements of an OpenVMS Cluster, including Alpha and VAX systems, different types of interconnects (e.g., Fibre Channel, Memory Channel, SCSI, CI, DSSI, LAN), and storage subsystems (disks, tapes, controllers).
3. Interconnects: A significant portion is dedicated to comparing and choosing different cluster interconnects, explaining their characteristics, advantages, throughput, supported adapters, and configuration guidelines for both node-to-node communication and shared storage.
4. Storage Subsystems: It provides guidance on selecting storage, estimating capacity, and utilizing performance and availability optimizers (e.g., disk striping, caching, volume shadowing). It covers CI-based, DSSI-based, SCSI-based, Fibre Channel-based, and host-based storage.
5. Multipath Configurations: The document extensively describes configuring multiple paths to SCSI and Fibre Channel storage to enhance availability and performance, detailing failover modes, device naming, and system parameters.
6. Availability & Scalability Strategies: Dedicated chapters explore strategies for configuring highly available clusters (emphasizing redundancy, failover, and specific configurations for LAN, DSSI, CI, and Memory Channel clusters, including multi-site and disaster-tolerant setups) and highly scalable clusters (addressing growth dimensions in CPU, memory, I/O, and distance, with examples for various interconnect types).
7. System Management: It offers strategies for managing OpenVMS Clusters, including system disk configurations (single vs. multiple), environment management (common vs. multiple environments), quorum strategies, state transition handling, and backup/storage management practices.

Appendices provide detailed technical summaries for specific interconnects like SCSI, Memory Channel, and the CI-to-PCI Adapter (CIPCA), along with in-depth information on multiple-site OpenVMS Cluster configurations.