The initial amount of memory in megabytes that the JVM should allocate
at startup. Defaults to 0, 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 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.
Example:
wrapper.java.initmemory=3
NOTE
Unless 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.
At times, it is necessary to set the memory thresholds relative to
the amount of physical memory available on the system. This propery
accepts a value between 1 and 100 which will translate into a size
in MBs. The value will be capped at 2048MB for 32-bit versions of
the Wrapper.
Example:
wrapper.java.initmemory.percent=60
In the above example, if 1GB (1024MB) of memory is installed on the
system, the initial memory will be set to 614MB.
NOTE
Java 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.
NOTE
This feature is currently not working correctly on AIX versions.
The problem is being looked into, but did not want to hold up the release.
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