Performance data organization

PMI data is organized in a centralized hierarchy of these objects:

• Instance
  An instance represents a node in the WebSphere Application Server administrative domain. No performance data is collected for the node itself.

• Server
  A server is a functional unit that provides services to clients over a network. No performance data is collected for the server itself.

• Module
  A module represents one of the resource categories for which collected data is reported to the PMI client. Each module has a configuration file in XML format. This file determines the organization of data and lists a unique identifier for each data counter in the module. Modules include enterprise beans, JDBC connection pools, J2C connection pool, Java Virtual Machine (JVM) run time (including Java Virtual Machine Profiler Interface (JVMPI)), servlet session manager, thread pools, transaction manager, Web applications, Object Request Broker (ORB), Workload Management (WLM), dynamic cache, and Web Services Gateway (WSGW).

• Submodule
  A submodule represents a fine granularity of a resource category under the module. For example, ORB thread pool is a submodule of the thread pool category. Submodules can contain other submodules.

• Counter
  A counter is a data type that contains performance information for analysis. Each module has an associated set of counters. The data points within a module are queried and distinguished by the Mbean ObjectNames or PerfDescriptors.

Use Tivoli Performance Viewer to view and manipulate the data for counters. A particular counter type can appear in several modules. For example, both the servlet and enterprise bean modules have a response time counter. In addition, a counter type can have multiple instances within a module.