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Add or Modify JVM options in z/OSMF Liberty Server

By ZHI LI posted Fri September 28, 2018 12:00 AM

  

This is an advanced configuration topic, if your z/OSMF is running well and smoothly on your system, there's no need to override the IBM shipped default jvm.options. Make sure you understand what you are doing before modifying the system.

Websphere Liberty allows user to specify JVM options during server start. Documents here has described how liberty jvm.options is working. When using Liberty in z/OSMF, you don't need to consider how jvm.options should be configured. The default shipped jvm.options is not editable and will fit almost everyone.

Here is the content of IBM shipped z/OSMF liberty jvm.options

-Xms128M
-Xmx1024M
-Xmns24M
-Xcompressedrefs
-Xquickstart
-Xshareclasses:none
-Djava.security.properties=/etc/zosmf/servers/zosmfServer/jvm.security.override.properties
-Dcom.ibm.ws.cache.CacheConfig.filteredStatusCodes=404

In some cases, if you have to update jvm.options. Here are instructions for how to do it.

  1. create an empty file, named local_override.cfg under $ZOSMF_DATA_DIR/configuration. If you use /var/zosmf, the full path is /var/zosmf/configuration/local_override.cfg. Skip this step if the override file already exists
  2. start a new line with JVM_OPTIONS= , here is a sample how it may look
    JVM_OPTIONS=-Doption=value

If you want to add more than one JVM option in z/OSMF, there are two ways to do it.

  1. Have all the JVM options specified in a single line, here is an example. Make sure you follow the pattern and symbols in your override file.
    JVM_OPTIONS='-Doption1=option1_value\n-Doption2=option2_value\n-Doption3=option3_value'
  2. Place all JVM options in another file and use -Xoptionsfile in override file. Here is an example of the override file
    JVM_OPTIONS='-Xoptionsfile='/var/zosmf/configuration/testfile''    
    Place all your JVM options in the testfile. Here is an example of the testfile
    -Xmx900m
    -Djavax.net.debug=true

You can also contact IBM support if you want help with configuring z/OSMF JVM options.


References:


1. z/OSMF Marketplace:
https://www.ibm.com/us-en/marketplace/zos-management-facility

2. z/OSMF Trial:
https://www.ibm.com/account/reg/us-en/signup?formid=urx-34578

3. z/OSMF One Stop Hub:
https://www.ibm.com/developerworks/community/blogs/e0c474f8-3aad-4f01-8bca-f2c12b576ac9/entry/z_OSMF_One_Stop_Hub?lang=en

4. z/OSMF Knowledge Center:
https://www.ibm.com/support/knowledgecenter/en/SSLTBW_2.3.0/com.ibm.zos.v2r3.izu/izu.htm