Guidelines for OpenVMS Cluster Configurations

Guidelines for OpenVMS Cluster Configurations

Order Number: BA554-90022

June 2010

OpenVMS Cluster availability, scalability, and system management benefits are highly dependent on configurations, applications, and operating environments. This guide provides suggestions and guidelines to help you maximize these benefits.

Revision/Update Information: This manual supersedes Guidelines for OpenVMS Cluster Configurations Version 7.3--2.

Software Version: OpenVMS Version 8.4 for Integrity servers
OpenVMS Alpha Version 8.4

Hewlett-Packard Company
Palo Alto, California

© Copyright 2010 Hewlett-Packard Development Company, L.P.

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The HP OpenVMS documentation set is available on CD-ROM.

Contents Index


This document can help you design an OpenVMS Cluster configuration to suit your business, application, and computing needs.

It provides information to help you choose systems, interconnects, storage devices, and software. It can also help you combine these components to achieve high availability, scalability, performance, and ease of system management.


This manual is applicable only for a combination of Integrity server systems and Alpha systems. For Alpha and VAX or Alpha systems combination, see the previous version of the manual.

Intended Audience

This document is for people who purchase or recommend the purchase of OpenVMS Cluster products and for people who configure OpenVMS Cluster systems. It assumes a basic understanding of computers and OpenVMS Cluster concepts.

About This Guide

OpenVMS Cluster systems are designed to act as a single virtual system, even though they are made up of many components and features, as shown in Figure 1.

Figure 1 OpenVMS Cluster System Components and Features

Understanding the components and features of an OpenVMS Cluster configuration can help you to get the most out of your cluster. Table 1 shows how this guide is organized to explain these cluster concepts.

Table 1 Document Organization
Read... Chapter Title So that you can...
Chapter 1 Overview of OpenVMS Cluster System Configurations Understand OpenVMS Cluster hardware, software, and general concepts
Chapter 2 Determining Business and Application Requirements Learn to analyze your business and application needs and how they apply to your cluster
Chapter 3 Choosing OpenVMS Cluster Systems Understand your computer requirements and make appropriate choices
Chapter 4 Choosing OpenVMS Cluster Interconnects Learn about cluster interconnects and make appropriate choices
Chapter 5 Choosing OpenVMS Cluster Storage Subsystems Learn to analyze your storage requirements and make appropriate choices
Chapter 6 Configuring Multiple Paths to SCSI and Fibre Channel Storage Learn how to configure multiple paths to storage using Parallel SCSI or Fibre Channel interconnects, thereby increasing availability
Chapter 7 Configuring Fibre Channel as an OpenVMS Cluster Storage Interconnect Learn how to configure an OpenVMS Cluster with Fibre Channel as a storage interconnect
Chapter 8 Configuring OpenVMS Clusters for Availability Understand how to increase the availability of a cluster system
Chapter 9 Configuring OpenVMS Clusters for Scalability Learn how to expand an OpenVMS Cluster system in all of its dimensions, while understanding the tradeoffs
Chapter 10 OpenVMS Cluster System Management Strategies Understand and deal effectively with some of the issues involved in managing an OpenVMS Cluster system
Appendix A SCSI as an OpenVMS Cluster Interconnect Configure multiple hosts and storage on a single SCSI bus so that multiple hosts can share access to SCSI devices directly
Appendix B MEMORY CHANNEL Technical Summary Learn why, when, and how to use the MEMORY CHANNEL interconnect
Appendix C Multiple-Site OpenVMS Clusters Understand the benefits, the configuration options and requirements, and the management of multiple-site OpenVMS Cluster systems

Related Documents

For additional information on the topics covered in this manual, see the following documents:

For additional information about HP OpenVMS products and services, see:

Reader's Comments

HP welcomes your comments on this manual. Please send your comments tor suggestions to:

How To Order Additional Documentation

For information about how to order additional documentation, see:


VMScluster systems are now referred to as OpenVMS Cluster systems. Unless otherwise specified, references to OpenVMS Clusters or clusters in this document are synonymous with VMSclusters.

In this manual, every use of DECwindows and DECwindows Motif refers to DECwindows Motif for OpenVMS software.

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Chapter 1
Overview of OpenVMS Cluster System Configuration

This chapter contains information about OpenVMS Cluster hardware and software components, as well as general configuration rules.

1.1 OpenVMS Cluster Configurations

An OpenVMS Cluster systems is a group of OpenVMS systems, storage subsystems, interconnects, and software that work together as one virtual system. An OpenVMS Cluster system can be homogeneous, that is, all systems are the same architecture (Integrity servers (based on the Intel Itanium architecture) or Alpha or VAX systems) all running OpenVMS. An OpenVMS Cluster can be heterogeneous, that is, a combination of two architectures with all systems running OpenVMS. The two valid combinations are Alpha and VAX or Alpha and Integrity server systems.

In an OpenVMS Cluster system, each system:

In addition, an OpenVMS Cluster system is managed as a single entity.


In a heterogeneous cluster, only one architecture is supported per system disk and per system boot block.

Table 1-1 shows the benefits that an OpenVMS Cluster system offers.

Table 1-1 OpenVMS Cluster System Benefits
Benefit Description
Resource sharing Multiple systems can access the same storage devices, so that users can share files clusterwide. You can also distribute applications, batch, and print-job processing across multiple systems. Jobs that access shared resources can execute on any system.
Availability Data and applications remain available during scheduled or unscheduled downtime of individual systems. A variety of configurations provide many levels of availability up to and including disaster-tolerant operation.
Flexibility OpenVMS Cluster computing environments offer compatible hardware and software across a wide price and performance range.
Scalability You can add processing and storage resources without disturbing the rest of the system. The full range of systems, from high-end multiprocessor systems to smaller workstations, can be interconnected and easily reconfigured to meet growing needs. You control the level of performance and availability as you expand.
Ease of management OpenVMS Cluster management is efficient and secure. Because you manage an OpenVMS Cluster as a single system, many tasks need to be performed only once. OpenVMS Clusters automatically balance user, batch, and print work loads.
Open systems Adherence to IEEE, POSIX, OSF/1, Motif, OSF DCE, ANSI SQL, and TCP/IP standards provides OpenVMS Cluster systems with application portability and interoperability.

1.2 Hardware Components

An OpenVMS Cluster system comprises many hardware components, such as systems, interconnects, adapters, storage subsystems, and peripheral devices. Table 1-2 describes these components and provides examples. See the Software Product Description for the complete list of supported components.

Table 1-2 Hardware Components in an OpenVMS Cluster System
Components Description Examples
System A cabinet that contains one or more processors, memory, and input/output (I/O) adapters that act as a single processing body.

Reference: See Chapter 3 for more information about OpenVMS systems.

OpenVMS Cluster systems can contain any supported Integrity sever, Alpha or VAX system.
Interconnect The hardware connection between OpenVMS Cluster nodes over which the nodes communicate.

Reference: See Chapter 4 for more information about OpenVMS Cluster interconnects.

An OpenVMS Cluster system can have one or more of the following interconnects:
  • Small Computer Systems Interface (SCSI) (node-to-storage only).
  • Serial Attached SCSI (SAS) (node-to-storage only).
  • Fibre Channel (node-to-storage only).
  • Ethernet, Fast Ethernet, Gigabit Ethernet, 10 Gigabit Ethernet. See the Software Product Description for the complete list of supported adapters.
Storage subsystems Devices on which data is stored and the optional controllers that manage the devices.

Reference: See Chapter 5 for more information about OpenVMS storage subsystems.

Storage subsystems can include:
  • SCSI or SAS disks and tapes
  • Storage arrays
  • SCSI or SAS storage controllers
  • InfoServer systems
Adapter Devices that connect nodes in an OpenVMS Cluster to interconnects and storage.

Reference: See Chapter 4 for more information about adapters.

The adapters used on Peripheral Component Interconnect (PCI) and PCI-Express (PCIe) systems include the following:
  • DE435 (Ethernet)
  • DEGPA (Gigabit Ethernet)
  • DEGXA (Gigabit Ethernet)
  • AB287A (10Gigabit Ethernet)
  • AD385A (10Gigabit Ethernet)
  • AD339A (Ethernet) (PCIe)
  • NC360M (Ethernet) (PCIe)

1.3 Software Components

OpenVMS Cluster system software can be divided into the following types:

1.3.1 OpenVMS Operating System Components

The operating system manages proper operation of hardware and software components and resources.

Table 1-3 describes the operating system components necessary for OpenVMS Cluster operations. All of these components are enabled by an OpenVMS operating system license with an OpenVMS Cluster license.

Table 1-3 Operating System Components
Component Function
Record Management Services (RMS) and OpenVMS file system Provide shared read and write access to files on disks and tapes in an OpenVMS Cluster environment.
Clusterwide process services Enables clusterwide operation of OpenVMS commands, such as SHOW SYSTEM and SHOW USERS, as well as the ability to create and delete processes clusterwide.
Distributed Lock Manager Synchronizes access by many users to shared resources.
Distributed Job Controller Enables clusterwide sharing of batch and print queues, which optimizes the use of these resources.
Connection Manager Controls the membership and quorum of the OpenVMS Cluster members.
SCS (System Communications Services) Implements OpenVMS Cluster communications between nodes using the OpenVMS System Communications Architecture (SCA).
MSCP server Makes locally connected disks to which it has direct access available to other systems in the OpenVMS Cluster.
TMSCP server Makes locally connected tapes to which it has direct access available to other systems in the OpenVMS Cluster.

Figure 1-1 shows how the hardware and operating system components fit together in a typical OpenVMS Cluster system.

Figure 1-1 Hardware and Operating System Components


Not all interconnects are supported on all three architectures of OpenVMS. The CI, DSSI, and FDDI interconnects are supported on Alpha and VAX systems. Memory Channel and ATM interconnects are supported only on Alpha systems.

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