Increasing JVM maximum memory allocation
The JVM can be configured with a larger heap with the -Xmx option (see oracle docs below). ISymphony allows you to configure any -X option in the jvm.args located in the root of the iSymphony installation directory (default: /opt/isymphony3/server/).
-Xms256m
-XX:MinHeapFreeRatio=30
-XX:MaxHeapFreeRatio=50
-XX:-OmitStackTraceInFastThrow
-Dcom.sun.management.jmxremote.port=8000
-Dcom.sun.management.jmxremote.authenticate=false
-Dcom.sun.management.jmxremote.ssl=false
Oracle JRockit Documentation
From: https://docs.oracle.com/cd/E13150_01/jrockit_jvm/jrockit/jrdocs/refman/optionX.html
-Xmx
This option sets the maximum Java heap size. The Java heap (the “heap”) is the part of the memory where blocks of memory are allocated to objects and freed during garbage collection. Depending upon the kind of operating system you are running, the maximum value you can set for the Java heap can vary.
Note: | -Xmx does not limit the total amount of memory that the JVM can use. |
Operation
Format: -Xmx<size>[g|G|m|M|k|K]
Combine -Xmx with a memory value
For Example:
java -Xmx:1g myApp
sets the maximum java heap to 1 gigabyte.
If you do not add a unit, you will get the exact value you state; for example, 64 will be interpreted as 64 bytes, not 64 megabytes or 64 kilobytes.
The -Xmx option and -Xms option in combination are used to limit the Java heap size. The Java heap can never grow larger than -Xmx. Also, the -Xms value can be used as “minimum heap size” to set a fixed heap size by setting -Xms = -Xmx when, for example, you want to run benchmark tests.
Known Issue for Linux Users
The JRockit JVM R26.0.0 on Linux IA32 can experience problems setting up memory for object allocation. When this happens, you will receive the following message:
[JRockit] ERROR: Fatal error in JRockit during memory setup phase. Try to reduce the heap size using -Xmx:<size>m, i.e. “-Xmx:16m”. Could not create the Java virtual machine.
and JRockit JVM will be exited.
The workaround for this situation is to try different -Xmx values until you find a heap size that is setup correct.
Note: | This known issue is valid for R26.0.0. |
Default Value
If you do not set this, the maximum java heap size depends on the platform and the amount of memory in the system as described in Table 2-6.
Table 2-6 Default Maximum Heap Sizes
Release | Platform | Default Maximum Heap Size |
|---|---|---|
R27.2 and older | Windows | 75% of total physical memory up to 1 GB |
R27.2 and older | Linux, Solaris | 50% of available physical memory up to 1 GB |
R27.3 and newer | Windows on a 64 bit platform | 75% of total physical memory up to 2 GB |
R27.3 and newer | Linux or Solaris on a 64 bit platform | 50% of available physical memory up to 2 GB |
R72.3 and newer | Windows on a 32 bit platform | 75% of total physical memory up to 1 GB |
R27.3 and newer | Linux on a 32 bit platform | 50% of available physical memory up to 1 GB |
Flags or Other Options Affected
None.
Exceptions
When using-Xmx, be aware of the following exceptions: