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Guidelines for OpenVMS Cluster Configurations

Guidelines for OpenVMS Cluster Configurations

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1.3.2 Networking Components

Table 1-4 describes the optional networking software that enables OpenVMS Cluster system nodes to communicate and share resources with other OpenVMS Cluster nodes.

Table 1-4 OpenVMS Cluster Networking Components
Optional Software Function
DECnet-Plus A network transport is necessary for internode communication.
Distributed File Service (DFS) Software to let you communicate and share resources among systems over extended distances.
Distributed File Service (DFS) Software to let you communicate and share resources among systems over extended distances.
LAT software Used with terminal server hardware to support Ethernet-based character cell terminals. During a system failure, LAT software automatically makes a connection to one of the remaining systems.
Advanced Server for OpenVMS and PATHWORKS for OpenVMS (Advanced Server) Client and server networking software that links PC systems into OpenVMS Cluster systems.
TCP/IP Services for OpenVMS software Provides Network File System (NFS) server capabilities for OpenVMS and supports Internet networking protocols.

1.3.3 Storage Enhancement Software

Optional storage enhancement software improves the performance or availability of storage subsystems.

Examples include:

For the latest information about OpenVMS storage management products, refer to the OpenVMS Products page of the OpenVMS web site:


1.3.4 System Management Software

System management software helps you manage your OpenVMS Cluster system.

Examples include:

1.3.5 Business Applications

Business applications are optional software packages that help you perform your business function.

Examples include:

1.4 Configuring an OpenVMS Cluster System

To take advantage of OpenVMS Cluster features and benefits, proper configuration is essential. An ideal OpenVMS Cluster configuration meets the following criteria:

Configuring your OpenVMS Cluster system requires careful planning because you need to consider many factors. You will probably modify plans as new factors arise. As your design evolves, you can weigh advantages against tradeoffs and make decisions that best meet your needs.

1.4.1 General Configuration Rules

The following general rules apply to OpenVMS Cluster systems:

In addition to these general rules, more detailed guidelines apply to different configurations. The rest of this manual discusses those guidelines in the context of specific configurations.

Chapter 2
Determining Business and Application Requirements

This chapter contains information about how to determine your OpenVMS Cluster business and application requirements.

2.1 Determining Business Requirements

The kinds of business requirements that you have affect the way that you configure your OpenVMS Cluster. Typical business requirements for an OpenVMS Cluster system include:

Some of these requirements may conflict with each other, such as scalability and physical location. For example, you may want to grow your OpenVMS Cluster, but you are limited by physical space or by the location of your systems. In situations like this, determine what your primary requirements are and where you are willing to make tradeoffs.

2.1.1 Budget

As with most business decisions, many of your choices will be determined by cost. Prioritizing your requirements can help you apply your budget resources to areas with the greatest business needs.

When determining your budget, plan for the initial system cost as well as the cost of ownership, which includes:

2.1.2 Availability

Determine how available your computing system must be. Most organizations fall into one of the three broad (and sometimes overlapping) categories shown in Table 2-1.

Table 2-1 Availability Requirements
Availability Requirements Description
Conventional For business functions that can wait with little or no effect while a system or application is unavailable.
24 x 365 For business functions that require uninterrupted computing services, either during essential time periods or during most hours of the day throughout the year. Minimal down time is acceptable.
Disaster tolerant For business functions with extremely stringent availability requirements. These businesses need to be immune to disasters like earthquakes, floods, and power failures.

Reference: For more information about availability, see Chapter 8 and Chapter 9 in this guide.

2.1.3 Scalability and Future Growth

Scalability is the ability to expand an OpenVMS Cluster in any system, storage, and interconnect dimension and at the same time fully use the initial configuration equipment. Scalability at the node level means being able to upgrade and add to your node's hardware and software. Scalability at the OpenVMS Cluster level means being able to increase the capacity of your entire OpenVMS Cluster system by adding processing power, interconnects, and storage across many nodes.

Among the low-end PCs and workstations, midrange departmental systems, and high-end data center systems offered by HP, each level has different processing, storage, and interconnect characteristics. Investing in the appropriate level means choosing systems that meet and perhaps exceed your current business requirements with some extra capacity to spare. The extra capacity is for future growth, because designing too close to your current needs can limit or reduce the scalability of your OpenVMS Cluster.

If you design with future growth in mind, you can make the most of your initial investment, reuse original equipment, and avoid unnecessary upgrades later.

Reference: See Chapter 10 for more help with analyzing your scalability requirements.

2.1.4 Physical Location Requirements

Physical restrictions can play a key role in how you configure your OpenVMS Cluster. Designing a cluster for a small computer room or office area is quite different from designing one that will be spread throughout a building or across several miles. Power and air-conditioning requirements can also affect configuration design.

You may want to allow room for physical growth and increased power and cooling requirements when designing your cluster.

Reference: See Section 8.6 and Section 10.7.8 for information about multiple and extended local area network (LAN) configurations.

2.1.5 Security

A secure environment is one that limits physical and electronic access to systems by unauthorized users. Most businesses can achieve a secure environment with little or no performance overhead. However, if security is your highest priority, you may need to make tradeoffs in convenience, cost, and performance.

Reference: See the HP OpenVMS Guide to System Security for more information.

2.2 Determining Application Requirements

Applications require processing power, memory, storage, and I/O resources. Determining your application requirements allows you to design an OpenVMS Cluster system that will meet your application needs. To determine your application requirements, follow the steps described in Table 2-2.

Table 2-2 Determining Your Application Requirements
Step Description
1 Make a list of the applications you currently run or expect to run.
2 For each application, write down your processor, memory, and I/O requirements (the application documentation provides this information.)

Processor power must be proportional to the number of calculations your applications perform, with enough additional processor power to oversee data transfer between nodes and between nodes and storage.

Memory capacity must be sufficient for your applications and for additional OpenVMS Cluster functions. Extra memory frequently improves system performance, so an initial investment in extra memory is probably a good one.

I/O performance requirements differ among applications. As you choose components such as nodes, interconnects, and adapters, monitor the inherent speed of each component so that you can choose faster components and eliminate potential bottlenecks.

3 Add up the CPU, memory, and I/O requirements for all of your applications. Add to this sum any special requirements, such as user requirements and peripheral devices.
4 When you have determined your total application requirements, be sure that your CPU, memory, and I/O resources exceed these requirements by 20%.

2.2.1 Adding Memory

Systems require approximately 5% more memory to run in an OpenVMS Cluster than to run standalone. This additional memory is used to support the shared cluster resource base, which is larger than in a standalone configuration.

With added memory, a node in an OpenVMS Cluster generally can support the same number of users or applications that it supported as a standalone system. As a cluster configuration grows, the amount of memory used for system work by each node may increase. Because the per-node increase depends on both the level of data sharing in the cluster and the distribution of resource management, that increase does not follow fixed rules. If the node is a resource manager for a heavily used resource, additional memory may increase performance for cluster users of that resource.

Reference: For more information about using additional memory to improve performance, refer to the OpenVMS Performance Management manual.

2.2.2 Balancing Processor, Memory, and I/O Resources

Application performance depends on adequate processor, memory, and I/O resources. Depending on your applications, one of these resources may be more important than the others. Consider your application requirements, and find a balance among these three resources that meets your requirements. Table 2-3 provides some guidelines on the resource requirements of different application types.

Table 2-3 Resource Requirements of Application Types
Application Type Example Requirement
General timesharing Program development, document preparation, office automation Processor and I/O intensive
Searching and updating a database and displaying reports Transaction processing, funds transfer, online order entry or reservation systems I/O and memory intensive
Simulation, modeling, or calculation Computer-aided design and manufacturing, image processing, graphics applications Processor and memory intensive

2.2.3 System Management Tools and Utilities

The OpenVMS operating system supports a number of utilities and tools that help you determine your business and application requirements in OpenVMS Cluster configurations. Table 2-4 describes many of these products. All are supplied with the OpenVMS operating system except for Disaster Tolerant Cluster Services (DTCS), which are customized for each environment. You can learn more about DTCS from your HP service representative and from the DTCS web site:


Table 2-4 System Management Tools from HP
Tool Function
Accounting utility Tracks how resources are being used.
AUTOGEN command procedure Optimizes system parameter settings based on usage.
Availability Manager HP Availability Manager is a system management tool that enables one or more OpenVMS Alpha or VAX nodes to be monitored on an extended local area network (LAN) from an OpenVMS Alpha or a Windows 2000 or XP node. This tool helps system managers and analysts target a specific node or process for detailed analysis. The analysis detects resource availability problems and suggests corrective actions. The data analyzer does not run on OpenVMS VAX which does not support Java.
HP Insight Management Agents for OpenVMS Enables you to look at devices on your OpenVMS systems. With the installation of Insight Manager on a Microsoft Windows server, you can manage all your platforms from a single Windows server.
HP WBEM Solutions for OpenVMS WBEM (Web-Based Enterprise Management) enables management applications to retrieve system information and request system operations wherever and whenever required. It allows customers to manage their systems consistently across multiple platforms and operating systems, providing integrated solutions that optimize your infrastructure for greater operational efficiency.
DECamds (Digital Availability Manager for Distributed Systems) Functionally similar to Availability Manager. Runs on OpenVMS VAX and OpenVMS Alpha.
Disaster Tolerant Cluster Services (DTCS) Tools and customized services for configuring and managing disaster-tolerant clusters that span different geographic sites.
Graphical Configuration Manager (GCM) A portable client/server application that gives you a way to view and control the configuration of partitioned AlphaServer systems running OpenVMS.
Galaxy Configuration Utility (GCU) A DECwindows Motif application that allows system managers to configure and manage an OpenVMS Galaxy system from a single workstation window.
Monitor utility Provides basic performance data.
OpenVMS Data Collector and Performance Analyzer (ECP Data Collector and ECP Performance Analyzer) The rights to use these ECP products are provided at no additional costs. The ECP Data Collector provides performance-data collection, archiving, reporting, and file display. The ECP Performance Analyzer assists in performance analysis and capacity planning of OpenVMS Cluster systems by identifying bottlenecks and recommending ways to fix problems. An API is provided within the Data Collector to gain direct access to the data it collects.
Performance Data Collector for OpenVMS (TDC V2) Used to gather performance data for an AlphaServer system running OpenVMS Version 7.3-2, or later. By default, TDC periodically collects and stores data in a file. Subsequently, user applications can retrieve data from the file.
Show Cluster utility Monitors activity and performance in a OpenVMS Cluster configuration.
OpenVMS Management Station Enables system managers to configure and manage user accounts, print queues, and storage across multiple OpenVMS Clusters and OpenVMS nodes. OpenVMS Management Station is a Microsoft® Windows®, and Windows® NT based management tool.
Systems Communications Architecture Control Program (SCACP) Designed to monitor and manage LAN cluster communications.
HP Web-Based Enterprise Services (WEBES) WEBES includes the System Event Analyzer (SEA) (formerly named Compaq Analyze), Computer Crash Analysis Tool (CCAT), DECevent, and the Revision and Configuration Management (RCM) tools. WEBES/SEA is the supported error log analysis tool for all AlphaServer DS, ES, and GS systems running OpenVMS, except for the AlphaServer GS60 and GS140. They must continue to use DECevent.

For more information about Availability Manager, HP Insight Management Agents for OpenVMS, Performance Data Collector for OpenVMS (TDC V2), and the OpenVMS Management Station, see the following web site:


For more information about the Accounting utility, the AUTOGEN command procedure, the Monitor utility, the Show Cluster utility, and the System Communications Architecture Control Program (SCACP), refer to the HP OpenVMS System Management Utilities Reference Manual.

For more information about the Graphical Configuration Manager (GCM) and the Galaxy Configuration Utility (GCU), refer to the HP OpenVMS Alpha Partitioning and Galaxy Guide.

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