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Monitor overall system health

Monitor should include, web servers, application servers, databases, back-end systems, and any other systems critical to running the website.

If any system has a problem, it might cause the servlet is slow message to appear. WAS provides Performance Monitoring Infrastructure (PMI) data to help monitor the overall health of the WAS environment. PMI provides average statistics on WAS resources, application resources, and system metrics.

Metric Meaning
Average response time How much time is spent in various parts of WAS and might quickly indicate where the problem is (for example, the servlet or the enterprise beans).
Number of requests (transactions) Look at how much traffic is processed by WAS, helping you to determine the capacity that we must manage. As the number of transactions increase, the response time of our system might be increasing. Showing the need for more system resources or the need to retune the system to handle increased traffic.
Number of live HTTP sessions The number of live HTTP sessions reflects the concurrent usage of our site. The more concurrent live sessions, the more memory is required. As the number of live sessions increase, we might adjust the session time-out values or the JVM heap available.
Web server thread pools Interpret the web server thread pools, the web container thread pools, and the Object Request Broker (ORB) thread pools, and the data source or connection pool size together. These thread pools might constrain performance due to their size. The thread pools setting can be too small or too large, causing performance problems. Setting the thread pools too large impacts the amount of memory needed on a system or might cause too much work to flow downstream if downstream resources cannot handle a high influx of work. Setting thread pools too small might also cause bottlenecks if the downstream resource can handle an increase in workload.
The web and EJB thread pools
Database and connection pool size
Java virtual memory (JVM) Use JVM metrics to understand the JVM heap dynamics, including the frequency of garbage collection. This data can help setting the optimal heap size. In addition, use the metric to identify potential memory leaks.
CPU Observe these metrics to know whether we are at or near the maximum capacity of our system resources.
I/O
System paging

(ZOS) WAS for z/OS relies on WLM services to collect some of the accounting and performance data.

(ZOS) Resource Measurement Facility (RMF™) and RMF-written System Management Facility (SMF) records present performance and accounting information to the WAS. In addition, the WAS for z/OS has SMF records that collect extra domain-specific information

(ZOS) Turn off the SMF records or RMF data using the administrative console and the SMFPRMxx parmlib member if we do not need the information. Use the SMFPRMxx parmlib member to control the detail of the WAS for z/OS SMF records. If we need SMF information, review the SMF records to ensure that we are collecting only the record types and details needed.

(ZOS) Set up your workload manager goals and filtering criteria is beyond the scope of this topic. We can classify work into service classes based on user ID and server name. Classify the control regions as reasonably high-performing system tasks


Tasks

  1. Enable PMI through the administrative console to begin data collection.
  2. Use Tivoli Performance Viewer or other performance monitoring and management solutions to monitor performance.
  3. Extend monitoring capabilities by developing our own monitoring applications or extending PMI.


Subtopics