Tuning Java virtual machines (JVM)
You can customize a server Java™ virtual machine (JVM) by editing the jvm.options file.
About this task
Decision Server Insights stores entities in a WebSphere® eXtreme Scale data cache. The cache is typically distributed across multiple runtime machines, which together form the eXtreme Scale data grid. To allow for maximum availability, the data is replicated between runtime servers using an eXtreme Scale transport mechanism known as IBM® eXtreme IO. The Java virtual machine provides an option to fix the amount of memory used by the eXtreme IO direct byte buffers. Runtime servers that are configured for production environments have a default value for each option, for example the MaxDirectMemorySize option. The other server types have no need for the direct byte memory setting.
The Xmx option specifies the maximum memory allocation pool for a JVM, while Xms specifies the initial memory allocation pool. Memory can be specified in multiple sizes, such as kilobytes and megabytes. If you adjust these settings, keep in mind that these options are for the JVM heap, and that the JVM can use more memory than just the size that is allocated to the heap.
For more information, see Configuring IBM eXtremeIO (XIO).
Procedure
- Open a <InstallDir>/runtime/wlp/usr/servers/server_name/jvm.options file in a suitable editor.
- Locate the option that you want to customize and change its default value.
- Save and close the file.