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Configuring JVM ParametersLocate this document in the navigation structure

Use

This procedure enables you to view and edit the Java Virtual Machine (JVM) parameters using Config Tool. The JVM is used for running the AS Java and all deployed applications. You can change values in the configuration template or for a specific instance.

If you want your settings to be valid for all instances, make the configurations on a template level.

The template configuration is valid for those instances that do not have custom configuration.

Note

You cannot delete default or inherited properties but only custom ones.

All the properties on an instance level are shown with their calculated values. That is, if a property has a link value (formula), in the table its calculated value is displayed. When you select the property, you can see its default link value in the Inherited Value field.

Prerequisites

Start the Config Tool by double-clicking the configtool script file in <SAP_install_dir>/<system_name>/<instance_name>/j2ee/configtool directory.

Procedure

Configuring JVM Environment Properties

  1. Choose the template or the instance you want to configure.

  2. Select VM Environment .

  3. Select a property from the table below.

  4. In Default/Inherited Property Data , you can see the default value of the property.

  5. In Custom property data , you can enter a new value for the property.

    Caution

    Avoid editing properties which values are not static (link values), such as DebugPort and ClassPath .

  6. Choose Set Custom Value .

  7. Choose Apply Changes.

  8. If you want to retrieve the default value of the property, choose Restore to Default Value .

  9. In order the changes to take effect, restart AS Java.

Configuring JVM Parameters on Template Level

  1. Select the template.

  2. Choose Start of the navigation path View  Next navigation step Expert Mode End of the navigation path.

  3. Select VM Parameters .

  4. In VM Type , you can make configuration changes that are specific for the selected JVM. These changes apply only if the current platform and vendor matches.

    The changes made in GLOBAL vendor apply to all vendors and platforms.

    Recommendation

    We recommend that you use sap vendor on all supported platforms.

  5. Via the following tabs you can configure the relevant template properties:

    • Memory - JVM memory settings.

      • JVM heap size

        Recommendation

        If you want to increase the JVM heap size, we recommend that you change only the maxHeapSize . Enter the required memory value (in megabytes) in the Custom value field.

      • JVM perm size

        If you enter an illegal value (for example, the value is not a number), the AS Java will not start. If you enter a value that is too low, the AS Java will experience problems and may restart.

    • System - all system properties usually specified with -Dxx=yy (for example, - DmyKey=myValue ).

      If you want to add a custom property, choose New . The Config Tool automatically adds -D to all newly-entered parameters.

    • Additional - any additional parameters, supported by the JVM (for example, -verbose:gc ). To add JVM parameters, choose New . The property is added to Custom parameters .

      The actual parameters used by a running JVM can be found in the development trace file of the corresponding server process.

      For example:

      Example

      key="-agentlib:myagent"

      value="port=12345,dir=C:/Mydir"

      This results in parameter: "-agentlib:myagent=port=12345,dir=C:/Mydir" .

    By default, all properties are enabled.

  6. To enable/disable a parameter from the Custom Parameters table, choose the parameter and then select Enable/Disable .

  7. To change the value of a property, select it from the table and in the Custom value field, enter the new value.

  8. Choose Set .

  9. Choose Apply Changes.

  10. In order the changes to take effect, restart AS Java.

Configuring JVM Parameters on Instance Level

  1. Choose the instance you want to configure.

  2. Select VM Parameters .

  3. From the table below, choose the relevant parameter.

  4. Enter the new value in the Custom Value field.

  5. To enable/disable a parameter from the Custom Parameters table, choose the parameter and then select Enable/Disable .

    Note

    For more advanced tasks (for example, to use a different "vendor-platform" combination), choose Start of the navigation path View Next navigation step Expert Mode End of the navigation path and then go to VM Type .

  6. Choose Set .

  7. Choose Apply Changes.

  8. If you want to retrieve the default value of the property, choose Restore to Default Value .

  9. In order the changes to take effect, restart AS Java.

Adding New JVM Parameters

  1. Choose the template or the instance you want to configure.

    Note

    To add VM parameters on a template level, choose Start of the navigation path View  Next navigation step Expert Mode End of the navigation path.

  2. Choose the VM Parameters tab.

    It is not possible to add new memory VM parameters but only system and custom ones.

  3. To add a system parameter, choose System .

    • Enter a name as required.

    • Optional: enter a value and description.

  4. To add a custom parameter, choose Additional

    • Select a VM parameter from the list.

    • Optional: enter a value if the Value field is available

    • Predefined description appears automatically. You can change or delete it.

  5. The new VM parameter appears in the Custom Parameters table.

  6. Choose Apply Changes.

  7. In order the changes to take effect, restart AS Java.