7.4.2 How to set the memory size in Java heap
Specify the estimated memory size with the options described in 7.2.6 Configuration of memory space used by JavaVM when using serial GC and JavaVM options. Shown below is how to set the memory size of the respective areas:
- Memory size of the entire Java heap
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Specify the maximum size with the -Xmxsize option and then specify the initial size with the -Xmssize option.
- Memory size of the Tenured area
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Specify the division ratio of the Tenured area and the New area for the entire Java heap with the -XX:NewRatio=value option. For example, in the case of -XX:NewRatio=5, the memory size specified with the -Xmxsize option is divided as follows:
Memory size of the New area: Memory size of the Tenured area = 1:5
- Memory size of the Survivor area and the Eden area
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Specify the division ratio of the Survivor area and the Eden area for entire New area with the -XX:SurvivorRatio=value option. Specify the division ratio with a numeric value that indicates how many times the Eden area is to be allocated for the From space and the To space of the Survivor area. For example, in case of -XX:SurvivorRatio=2, the memory size of the New area decided by the -XX:NewRatio=value option is divided as follows:
Memory size of the Eden area : Memory size of the From space : Memory size of the To space = 2:1:1
- Memory size of the Metaspace area
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Specify the maximum size with the -XX:MaxMetaspaceSize=size option and then specify the initial size with the -XX:MetaspaceSize=size option.