Document revision date: 15 July 2002

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
Compaq DECnet--Plus	A network transport such as DECnet--Plus or Compaq TCP/IP Services for OpenVMS software is necessary for internode communication.
Compaq DECnet--Plus System Services (DSS) products	Software to let you communicate and share resources among systems over extended distances. Products include VAX Distributed File Service (DFS), VAX Distributed Name Service (DNS), and the VAX Distributed Queuing Service (DQS).
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.
Compaq 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:

• Compaq Volume Shadowing for OpenVMS (redundant arrays of independent disks [RAID] level 1)
• Compaq DECram for OpenVMS (random access memory [RAM] disk)
• Compaq RAID Software for OpenVMS (supports RAID level 0 arrays (disk striping) and RAID level 5 arrays (disk striping with parity)
• Compaq Hierarchical Storage Manager (HSM)

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

http://www.openvms.compaq.com/

1.3.4 System Management Software

System management software helps you manage your OpenVMS Cluster system.

Examples include:

• Compaq Availability Manager and DIGITAL Availability Manager for Distributed Systems (DECamds)
  Note: Availability Manager and DECamds are provided with the OpenVMS operating system.
• Compaq Archive/Backup System for OpenVMS
• Compaq Code Management System for OpenVMS
• Compaq Graphical Configuration Manager (GCM)

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

Examples include:

• Database systems, such as Oracle Rdb, Oracle CDD/Repository, and Sybase
• Transaction processing systems, such as Compaq ACMSxp for OpenVMS Alpha
• Transaction routing systems, such as Reliable Transaction Router
• OpenVMS e-Business Infrastructure applications, such as Compaq COM for OpenVMS and Compaq Secure Web Server for OpenVMS Alpha (CSWS), which are included on the OpenVMS e-Business Infrastructure CD-ROM.

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

• Provides the best combination of hardware and software components to meet your business requirements.
• Strategically distributes your budget dollars to return maximum value in the areas that are high priority for your business.
• Meets your current needs and retains your investment as your business needs grow and change.

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:

• A node is an OpenVMS system. An OpenVMS Cluster system cannot contain more than 96 Alpha and VAX (combined total) nodes.
• An Alpha and a VAX system can not boot from the same system disk. System disks are architecture specific and can be shared only by systems of the same architecture.
  Cross-architecture satellite booting is supported. Alpha satellites (clients) can boot from a VAX boot server, and VAX satellites (clients) can boot from an Alpha boot server.
• Every OpenVMS node must be able to communicate directly with every other OpenVMS Cluster node.
  Configurations that use a shared (multihost) SCSI bus or a shared (multihost) Fibre Channel interconnect must also be configured with any of the other supported OpenVMS Cluster interconnects, because node-to-node communication does not occur across the SCSI bus or the Fibre Channel.
  Reference: See Section 4.8 for more information about the SCSI interconnect and Section 4.6 for more information about the Fibre Channel interconnect.
  Configurations that use a MEMORY CHANNEL interconnect must also be configured with any of the other supported OpenVMS Cluster interconnects for access to storage. Storage cannot be configured on MEMORY CHANNEL.
  Reference: See Section 4.7 for more information about MEMORY CHANNEL.
• An OpenVMS Cluster node, storage controller, or storage device can participate in only one OpenVMS Cluster system at a time.
• DECnet--Plus software is not required in an OpenVMS Cluster configuration. However, DECnet--Plus is necessary if internode process-to-process communication using DECnet mailboxes is needed. Starting with OpenVMS Version 7.0, the Monitor utility uses a TCP/IP or DECnet transport, as appropriate, for intracluster communication.

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.

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:

• Budget
• Availability
• Scalability and future growth
• Physical location requirements
• Security

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:

• Service and update
• Power consumption
• Cooling
• System management

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 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 Digital, 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 10.7.7 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 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 Compaq service representative and from the DTCS web site:

http://www.compaq.co.uk/globalservices/continuity/dis_clus.stm

Table 2-4 System Management Tools

Tool	Function
Accounting utility	Tracks how resources are being used.
AUTOGEN command procedure	Optimizes system parameter settings based on usage.
Availability Manager	Collects and analyzes data from multiple nodes simultaneously, directing all output to a centralized DECwindows display. The analysis detects resource availability problems and suggests corrective actions. Runs on OpenVMS Alpha and Windows-based systems.
Compaq Management Agents for OpenVMS	Enable you to look at devices on your OpenVMS systems. With the installation of Compaq Insight Manager XE on an NT server, you can manage all your Compaq platforms from a single NT server.
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.
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.
Web-Based Enterprise Services (WEBES)	WEBES includes Compaq Analyze, Compaq Crash Analysis Tool (CCAT), DECevent, and the Revision and Configuration Management (RCM) tools. Compaq Analyze 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, Compaq Management Agents for OpenVMS, and the OpenVMS Management Station, see the following web site:

http://www.openvms.compaq.com/openvms/system_management.html

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 OpenVMS System Management Utilities Reference Manual.

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

2.2.4 System Management Tools from OpenVMS Partners

OpenVMS Partners offer a wide selection of tools to meet diverse system management needs, as shown in Table 2-5. The types of tools are described in the following list:

• Schedule managers
  Enable specific actions to be triggered at determined times, including repetitive and periodic activities, such as nightly backups.
• Event managers
  Monitor a system and report occurrences and events that may require an action or that may indicate a critical or alarming situation, such as low memory or an attempted security breakin.

• Console managers
  Enable a remote connection to and emulation of a system console so that system messages can be displayed and commands can be issued.
• Performance managers
  Monitor system performance by collecting and analyzing data to allow proper tailoring and configuration of system resources. Performance managers may also collect historical data for capacity planning.

Table 2-5 System Management Products from OpenVMS Partners

Business Partner	Product	Type or Function
BMC	Perform and Predict	Performance and capacity manager
	Patrol for OpenVMS	Event manager
	ControlM	Console manager
Computer Associates	Advise IT	Performance manager
	Command IT	Console manager
	Schedule IT	Schedule manager
	Watch IT	Event manager
	Unicenter TNG	Package of various products
Fortel	Sightline	Performance manager
Heroix	RoboMon	Event manager
	RoboCentral	Console manager
ISE	Schedule	Schedule manager
Ki NETWORKS	CLIM	Console manager
ORSYP	Dollar Universe	Schedule manager
RAXCO	Perfect Cache	Storage performance
	Perfect Disk	Storage management
TECsys Development Inc.	Console Works	Console manager

For current information about OpenVMS Partners and the tools they provide, access the OpenVMS web site:

http://www.openvms.compaq.com/openvms/system_management.html

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