HP OpenVMS Systems Documentation
Guidelines for OpenVMS Cluster Configurations
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.
1.3.3 Storage Enhancement Software
Optional storage enhancement software improves the performance or availability of storage subsystems.
For the latest information about StorageWorks products, refer to the StorageWorks web site, which you can select from the Compaq World Wide Web site:
1.3.4 System Management Software
System management software helps you manage your OpenVMS Cluster system.
1.3.5 Business Applications
Business applications are optional software packages that help you perform your business function.
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
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.
|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.|
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.
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.
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.
|1||Make a list of the applications you currently run or expect to run.|
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%.|
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.
|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|
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 and indicates whether each is supplied with the OpenVMS operating system or is an optional product.
|Tool||Supplied or Optional||Function|
|Accounting utility||Supplied||Tracks how resources are being used.|
|AUTOGEN command procedure||Supplied||Optimizes system parameter settings based on usage.|
|DECamds (Digital Availability Manager for Distributed Systems)||Supplied||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.|
|Availability Manager||Supplied||Functionally similar to DECamds but runs on Windows-based systems and on OpenVMS Alpha.|
|Monitor utility||Supplied||Provides basic performance data.|
|POLYCENTER Capacity Planner||Optional||Provides a capacity-planning function to help analyze how changes in the configuration affect user performance.|
|Show Cluster utility||Supplied||Monitors activity and performance in a OpenVMS Cluster configuration.|
|DECevent||Supplied||Monitors system and device status and predicts failures.|
|OpenVMS Management Station||Supplied||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.|
|Web-Based Enterprise Services (WEBES)||Supplied||WEBES includes Compaq Analyze, Compaq Crash Analysis Tool (CCAT), DECevent, and the Revision and Configuration Management (RCM) tools. These are the supported tools for all AlphaServer DS, ES, and GS systems running OpenVMS, except for the AlphaServer GS60 and GS140, which must continue to use DECevent.|
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:
|Business Partner||Product||Type or Function|
|Enterprise ControlStation||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|
|Global Maintech||VCC||Console manager|
|Ki NETWORKS||CLIM||Console manager|
|XL Software||Dollar Universe||Schedule manager|
|RAXCO||Perfect Cache||Storage performance|
|Perfect Disk||Storage management|
|TDI||Console Works||Console manager|