IBM BS029ML Self Help Guide - Page 34

2.2.2 Node characterization at the specification level It is strongly advised that the specification level attributes for each node in a contending WebSphere Portal Server architecture are clearly defined and documented. As such, each node should be described in terms of the functional and non-functional requirements and how those requirements are met. Table 2-3 gives an overview of node specifications. Table 2-3 Node specification Specification Level Node Example: System x™ Attributes Presentation Deployment Units Execution Deployment Units Data Deployment Units This section identifies and describes the major DUs (Deployment Units) associated with a node. A DU is considered as a single unit for placement considerations. Furthermore, it is often important to distinguish between the placement of presentation, execution, and data DUs. Example: J2EE artifacts, such as .ear files and .jar files, may be considered as Data DUs, while WebSphere Application Server remains an Execution DU. It is important to recognize that multiple DUs may be grouped together on the same node, where practical. Environments Example: Production - Based on 100% of the required NFR capacity. Hardware Example: pSeries®. Operating System Example: AIX® 5L™ V5.3.0.0-0.3. Non-Functional Requirements Availability Example: Minimum of two physical nodes, one in each data center, configured as a single active-active cluster across both data centers. Capacity Example: Each node should be able to handle 50% of the required capacity. However, as this component is part of the shared common network infrastructure core, the total consolidated capacity must be capable of delivering a guaranteed Quality of Service. Scalability Example: Implied horizontal scalability through the addition of extra physical nodes in each data center. Implied vertical scalability for Java based components, hardware resources permitting. Disaster Recovery and Resilience Example: In the case of the failure of one physical node, the others will continue to function with a reduction in total capacity. In the case of the failure of a software component on one of the physical nodes, the other collocated software components will continue to function. Depending on the type of failure the recovery characteristics will be different. For example, the failover from a network connection failure has different fail-over characteristics from that of a WebSphere Portal Server cluster member JVM crash. System Management Example: Integration of system event monitoring with client X's enterprise monitoring infrastructure. 20 IBM WebSphere Portal V6 Self Help Guide