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Zing Virtual Machine Post Installation Tasks

The following post-installation steps are not directly required when starting to use Zing, but it is recommended to go through them to avoid later problems in production systems.

Transferring JDK Customizations

If you have applied customizations to the existing non-Zing JVM installation location, you might need to transfer those to the Zing.

Those customizations can be, for example, JAR files added to the directory $JAVA_HOME/jre/lib/ext or changes in the security settings below $JAVA_HOME/jre/lib/security. Zing offers the same directories to store custom JARs and security policies.

Ensuring Sufficient Virtual Memory Areas

Depending on the application activity and its Java object sizes, Zing requires a larger number of virtual memory areas (VMAs) than the Linux default of 65530. Most applications on Zing won't need a change here, but to be on the safe side, set the upper limit to four times the system RAM size in MBytes. vm.max_map_count Linux system parameter defines this limit.

To keep the configuration simple when managing multiple hosts, set it on all hosts to the same value as setting it too large doesn't cause any harm. A value of 1,000,000 (one million) is recommended for systems with a RAM size of up to 256 GBytes. To set the recommended value, complete the following steps:

  1. Add the following line to the file /etc/sysctl.conf:
  2. To activate the setting without reboot, run:
    sudo sysctl -p
  3. To check the setting on any system, type:
    cat /proc/sys/vm/max_map_count




Last modified: December 10, 2019

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