Post-Installation Configuration Options › How to Complete the Installation › Modify the External ActiveMQ Memory Limit After Installation (Optional)

Modify the External ActiveMQ Memory Limit After Installation (Optional)

The Data Aggregator installer calculates the memory that is needed on your system to accommodate the ApacheMQ process. However, you can manually modify the memory limit settings to fine tune ActiveMQ on your Data Aggregator system. For example, you can modify the settings under the following circumstances:

• When the system memory has changed.
• When the number of Data Collector systems have changed.
• To optimize the memory settings.
• When you have determined that ActiveMQs performance is degraded, by monitoring either the JConsole or the CA Performance Management custom chart with ActiveMQ metrics.

Follow these steps:

1. Calculate the amount of memory for ActiveMQ based on the following settings:

   Maximum java heap size

   This value is set to 20% system memory by default. The minimum value is 512M.

   Initial minimum java heap size

   This value should be 50% of maximum java heap size.

   Memory limit for all messages

   This value should be 50% of the maximum java heap size.

   Memory limit per queue

   This value should be calculated based on how many Data Collector installations you have.

   Example: The memory per queue

   (system memory for all messages)/5/(Data Collector count)

2. Log in to the computer where Data Aggregator is installed. Log in as the root user or a sudo user with access to a limited set of commands.

   Note: For more information about the sudo user, see the Data Aggregator Installation Guide.

3. Type the following command to stop the ActiveMQ broker:

   /etc/init.d/activemq stop
   

4. Modify the java heap size for ActiveMQ:
   1. Access the activemq file under broker/apache-activemq-version/bin.
   2. Locate the line that defines ACTIVEMQ_OPTS_MEMORY.
   3. Change –Xms to be the Initial minimum java heap size.
   4. Change –Xmx to be the Maximum java heap size.
   5. Save the file.
5. Modify the ActiveMQ memory limit for the producer flow control:
   1. Access the activemq.xml file in the Data Aggregator installation directory/broker/apache-activemq-version/conf file.
   2. Locate the following line and change the value to Memory limit for all messages:

      <memoryUsage limit=”value”/>
      

   3. Locate the following line, change the value to Memory limit per queue:

      <policyEntry queue=">" producerFlowControl="true" memoryLimit="value"/>
      

   Note: For more information, refer to http://activemq.apache.org/producer-flow-control.html.

6. Type the following command to start the ActiveMQ broker:

   ./etc/init.d/activemq start
   

   Your new settings are activated.

More information:

How to Complete the Installation