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WebSphere MQ Parameters
Your processing volumes and the number of WebSphere MQ queue consumers and
producers that you expect to start might require you to change the channel and log
parameters in the qm.ini or mqs.ini file.
Channel
Each started thread that reads from or writes to the WebSphere MQ queues
requires a channel. If you start 20 JVMs with 5 threads each, you will need at least
100 channels (the default value). You may also have to increase the number of
channels if you have workloads that open and close the JMS/MQ connections
rapidly.
If you experience messages indicating that the maximum number of channels has
been reached, do the following:
v Check to see if there is a connection or channel leak. Run the following
command to see how many active channels are used. YOUR_QM_NAME should be
replaced with your real Queue Manager name.
echo "dis chs(*)" | runmqsc YOUR_QM_NAME | grep RUNNING | wc -l
v You may have to run each workload at peak production loads in your test
environment to diagnose channel leaks.
v If you suspect that channels are not getting reclaimed fast enough or if your
TCP/IP connection is not reliable, you should set the following parameters. The
KeepAlive parameter tells the queue manager to check the existence of the client.
If the client is not there, the queue manager will reclaim the channel. The
MaxChannels parameter defaults to 100. In production settings, that parameter
could grow to a much higher number like 300 or 500.
TCP:
KeepAlive=YES
Channels:
MaxChannels=300
MaxActiveChannels=100
Log Files
WebSphere MQ uses log files to maintain message integrity in the event of a queue
manager restart or a media failure.
The number of log files depends on your configuration, the size of the messages,
the logging type, and the message volumes. You should performance test your
application at or above peak production loads to see if the default WebSphere MQ
log settings are sufficient. If you are using CIRCULAR logging, the following may
be reasonable starting values:
Log:
LogPrimaryFiles=4
LogSecondaryFiles=1
LogFilePages=65536
LogType=CIRCULAR
LogBufferPages=0
If you use LINEAR logging (for example, to survive media failure), you will have
to set LogPrimaryFiles higher.
202 Sterling B2B Integrator: Performance Management