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Tune considerations using the JSR 289 Application Router with multiple applications
This topic describes performance adjustments and considerations using the JSR 289 Application Router with multiple applications.
With WAS v8 you can configure the server to use the High Performance Extensible Logging (HPEL) log and trace infrastructure instead of using SystemOut.log , SystemErr.log, trace.log, and activity.log files or native z/OS logging facilities. If you are using HPEL, you can access all of your log and trace information using $PROFILE/bin/LogViewer.sh. See the information about using HPEL to troubleshoot applications for more information on using HPEL.New feature:
When you deploy more than one application, you might see the following errors in the log files when heavy SIP protocol traffic exists for a single application server or cluster of servers:
- Unexpected and excessive SIP application 503 Server Unavailable error messages
- Proxy and Server overload errors
These error messages do not occur when you deploy one application. The proxy server and SIP containers are not synchronized when they are tracking the amount of messages that are flowing through the system. Using the application router, multiple messages might be routed between applications. These messages cause container message counters to increment even though the messages do not flow through the proxy server.
We can diagnose this problem when we have the following conditions:
- Heavy SIP protocol traffic exists.
- Multiple applications are deployed on a single node or cluster.
Check the proxy server, the application server SystemOut.log log files, or both for an unexpected overload condition that is detected at the proxy server, the application server, or both. Also, look for 503 Server unavailable messages that are logged from the SIP application.
Resolve the problem
Messages are shared between applications at the SIP container before they are sent to the proxy server.
To avoid these error messages and a decrease in SIP performance, tune the SIP containers to consider the additional SIP messages that are generated when using the application router with multiple applications. Complete the following steps in the admin console to tune the SIP containers:
- Expand Servers > Server Types and click WebSphere application servers > server_name
- Under Container Settings, expand SIP Container Settings and click SIP container.
- Increase the Maximum messages per averaging period value to compensate for the anticipated increase in messages that are generated by the SIP application router.
- Increase the Maximum application sessions value to compensate for the increased Maximum messages per averaging period value.
Example
The proxy server cannot detect the amount of messages that are generated at the server. However, modifications to the following settings might increase the messaging capacity at the containers for the number of applications that are deployed per container.
DAR and CAR SIP container tuning values.
This table lists the DAR and CAR SIP container tuning values for the number of applications that are deployed per container.
SIP Container Single Deployed SIP Application Three Deployed SIP Applications Maximum messages per averaging period value = 26640 value = 79920 Maximum application sessions value = 36000 value = 96000 The values for the Maximum messages per averaging period and Maximum application sessions fields depend on the processing power, memory, and the deployed application. Use the values for these fields as listed in the SIP container settings topic and adjust them to meet the needs of the environment.
SIP container settings