Configuring JVM Parameters

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

If you want your settings to be valid for all instances, select the template and choose the VM Parameters or VM Environment tab.

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

Note Note

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

End of the note.

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

Choose the template or the instance you want to configure.
Select VM Environment.
Select a property from the table below.
In Default/Inherited Property Data, you can see the default value of the property.
In Custom property data, you can enter a new custom value for the property.

Caution
Avoid editing properties which values are not static, such as DebugPort and ClassPath.

End of the caution.
Choose Set Custom Value and then (Apply Changes).

Configuring JVM Parameters on Instance Level

Choose the instance you want to configure.
Select VM Parameters.
From the table below, choose the relevant parameter.
Enter the new value in the Custom Value field.
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, if you want to use a different “vendor-platform” combination), choose View Expert Mode and then go to VM Type.

End of the note.
Choose Set and then (Apply Changes).

Configuring JVM Parameters on Template Level

Select the template.
Choose View Expert Mode .
Select VM Parameters.
In VM Type, you can make configuration changes that are specific to 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.

End of the recommendation.
Via the following tabs you can view the template properties contained therein:
- 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 needed memory value (in megabytes) in the Custom value field.
    
    End of the recommendation.
  - 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"
  
  Results in parameter: "-agentlib:myagent=port=12345,dir=C:/Mydir".
  
  End of the example.
By default, all properties are enabled.
To enable/disable a parameter from the Custom Parameters table, choose the parameter and then select Enable/Disable.
To change the value of a property, select it form the table and in the Custom value field, enter the new value.
Choose Set and then (Apply Changes).