This topic describes performance adjustments and considerations
using the JSR 289 Application Router with multiple applications.
New feature: This topic
references one or more of the application server log files. Beginning
in WebSphere Application Server Version 8.0 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 the LogViewer command-line tool from your
server profile bin directory. See the information about using HPEL
to troubleshoot applications for more information on using HPEL.
newfeat
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
Note: These error messages do not occur when you deploy one application.
The
proxy server and Session Initiation Protocol (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.
You can diagnose this problem when you 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.
Resolving 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 administrative console to tune the SIP containers:
- Expand and click
- 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.
Table 1. 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 |
Note: 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 your environment.