8.4.  Use the Performance Monitoring Infrastructure (PMI) metrics and poll MBeans for performance data.

[Note]

Retrieving performance data with PerfServlet

The PerfServlet is used for simple end-to-end retrieval of performance data that any tool, provided by either IBM or a third-party vendor, can handle.

The servlet provides a way to use an HTTP request to query the performance metrics for an entire WebSphere Application Server administrative domain. Because the servlet provides the performance data through HTTP, issues such as firewalls are trivial to resolve.

The PerfServlet provides the performance data output as an XML document, as described in the provided document type description (DTD). In the XML structure, the leaves of the structure provide the actual observations of performance data and the paths to the leaves that provide the context.

The PerfServlet is a sample monitoring tool that uses WebSphere Application Server administration and monitoring interfaces to expose performance data. Using the PerfServlet is not intended for real-time performance monitoring in production environments or for use in large topologies. For these environments you should use the Tivoli Performance Viewer for WebSphere Application Server.

Specific best practices for the PerfServlet are the following:

Starting with version 6.0, the PerfServlet in WebSphere Application Server uses the JMX Perf MBean interface to retrieve the PMI data and outputs an XML document that uses the Java Platform, Enterprise Edition (Java EE) 1.4 Performance Data Framework to describe the statistics. The PerfSerlvet in can also provide an output that is compatible with the PerfServlet 5.0. To provide PerfServlet 5.0 compatible output it uses the PMI client interface.

The performance servlet .ear file PerfServletApp.ear is located in the WAS_HOME/installableApps directory, where WAS_HOME is the installation path for WebSphere Application Server.

Starting with version 6.1, you must enable application security to get the PerfServlet working.

The performance servlet is deployed exactly as any other servlet. To use it, follow these steps:

  1. Deploy the servlet on a single application server instance within the domain.

  2. After the servlet deploys, you can invoke it to retrieve performance data for the entire domain. Invoke the performance servlet by accessing the following default URL:

    http://hostname/wasPerfTool/servlet/perfservlet
    								

The performance servlet provides performance data output as an XML document, as described by the provided document type definition (DTD). The DTD is located inside the PerfServletApp.ear file.

Figure 8.4. Performance Servlet sample output

Performance Servlet sample output


The Performance Servlet provides a basic filter functionality for the XML results. To filter the results simply add parameters to the URL. IBM defined serveral parameters:

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