- Documentation
- Configuration Property Overview
- JVM Configuration
- wrapper.java.initmemory Property
wrapper.java.initmemory |
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The initial amount of memory in megabytes that the JVM should allocate at startup. The default value is "0" (zero), which will cause the JVM's default value to be used. If a non-zero value is specified for this property then an appropriate -Xms parameter will be added to the Java command generated by the Wrapper. If specified, the initial memory must be less than or equal to the value set for the wrapper.java.maxmemory property. If this property is set to "0" (zero), then it is also possible to specify the -Xms parameter manually using the wrapper.java.additional.<n> property. This value can affect the startup time of the application. Startup time is optimized when this value is fairly close to the actual amount of memory required by the application once it has been started. The default value for Windows and Linux JVMs is usally 2Mb, but Solaris JVMs require a minimum of 3Mb. Valid values are in the range 1 to the value of the wrapper.java.maxmemory property, which itself does not have an upper limit.
NOTEUnless you really do know everything there is to know about memory and Garbage Collection in Java, I would recommend reading through the following document. It describes in detail how the initial and maximum memory values affect Java performance and also goes into detail about what can be done to improve that performance for a given application. |
wrapper.java.initmemory.percent |
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At times, it is necessary to set the memory thresholds relative to the amount of physical memory available on the system. This property accepts a percentage value between 1 and 100 which will translate into a size in MBs. For 32-bit versions of the Wrapper, the value will be calculated relative to lower of physical memory and 2048MB.
In the above example (60%), if 1GB (1024MB) of memory is installed on the system, the initial memory will be set to 614MB (=1024 x 60%). NOTEJava behaves very poorly if the JVM has any of its memory swapped so it is important to take the OS requirements and any other applications into account when deciding on a safe memory level. NOTEThis feature is currently not working correctly on AIX versions. The problem is being looked into, but did not want to hold up the release of Wrapper due to only this reason. |
Reference: Java Memory |
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