G1 Eden Space and G1 Survivor Space

[BHARATH ANCHALKAR]

Can anyone please help me understand the impact of G1 Eden Space and G1 Survivor Space using 100% of memory ? How can I modify the memory usage in setenv.sh to bring down the usage of these two ? 

[Luca Miceli]

The impact of a full heap utilization are related to worse performance of your Java Virtual Machine and also low application performance. You have to consider that an Heap out of Memory Exception can also occurs.

In order to manage your heap available space you need to specify these command line options whenever you run java:

• -Xms:<size>, which sets the initial and minimum heap size
• -Xmx:<size>, which sets the maximum heap size

For example:

java -Xms:1g -Xmx:1g

In your setenv.sh you can search a variable like this and place your parameters

JAVA_OPTS="-Xms2048m -Xmx3072m -XX:MaxPermSize=3072m

You will find further details on Memory management in JAVA, and other command lines option at this link:

https://docs.oracle.com/cd/E13150_01/jrockit_jvm/jrockit/geninfo/diagnos/memman.html