Gc.log

[alex russo]

I apologize if this question does not belong to this thread, please let me know and I will post it to the right thread.

Question: Why would the GC.LOG write differently from one server to another.
can some one explain why some jvm denote "PSYoungGen" as "new generation" and then "PSOldGen" as "tenured generation".

also the in jdk1.7.0_11 why would it denote "PSOldgen" as "ParOldGen"

I do not have the parameter in my config.xml : XX:+UseParallelGC , the reason I am quoting this is

From link: http://www.oracle.com/technetwork/java/javase/7u4-relnotes-1575007.html
Parallel Old GC (-XX:+UseParallelOldGC) is now enabled by default whenever -XX:+UseParallelGC is enabled. To revert to the previous default behavior, use the option -XX:-UseParallelOldGC on the java command line.

what is the preferred garbage collection in jdk1.7 when I don't denote "<jvm-options>-client</jvm-options>" or "<jvm-options>-server</jvm-options>"

any suggestion is highly appreciated.

[Jeff Verdegan]

GC approaches and implementations change from version to version as improvements are made, so it's not surprising that the logging also changes to reflect that.

[alex russo]

Jeff Verdegan wrote:GC approaches and implementations change from version to version as improvements are made, so it's not surprising that the logging also changes to reflect that.

thanks for your prompt response jeff, but let me give you my example:

I have 2 environments running in glassFish a Staging and Prod, exact version of java

In staging the gc.log denotes the oldgen as "tenured generation"
In prod the gc.log denotes the oldGen as "ParOldGen"

the jvm-options i am using is below and its same in both environments. So trying to understand what is causing the difference -any dependency on the OS - i don't think so


<jvm-options>-Dcom.sun.enterprise.server.logging.max_history_files=15</jvm-options>
<jvm-options>-Xloggc:/a01/apps/xxx/glassfish/domains/domain1/logs/gc.log</jvm-options>
<jvm-options>-XX:+PrintHeapAtGC</jvm-options>
<jvm-options>-XX:+PrintTenuringDistribution</jvm-options>
<jvm-options>-XX:+PrintGCTimeStamps</jvm-options>
<jvm-options>-Dlog4j.configuration=file:///${com.sun.aas.instanceRoot}/config/log4j.properties</jvm-options>
<jvm-options>-XX:MaxPermSize=512m</jvm-options>
<jvm-options>-client</jvm-options>
<jvm-options>-Djava.endorsed.dirs=${com.sun.aas.installRoot}/lib/endorsed</jvm-options>
<jvm-options>-Djava.security.policy=${com.sun.aas.instanceRoot}/config/server.policy</jvm-options>
<jvm-options>-Djava.security.auth.login.config=${com.sun.aas.instanceRoot}/config/login.conf</jvm-options>
<jvm-options>-Dsun.rmi.dgc.server.gcInterval=3600000</jvm-options>
<jvm-options>-Dsun.rmi.dgc.client.gcInterval=3600000</jvm-options>
<jvm-options>-Xmx2048m</jvm-options>
<jvm-options>-Xms2048m</jvm-options>
<jvm-options>-Djavax.net.ssl.keyStore=${com.sun.aas.instanceRoot}/config/keystore.jks</jvm-options>
<jvm-options>-Djavax.net.ssl.trustStore=${com.sun.aas.instanceRoot}/config/cacerts.jks</jvm-options>
<jvm-options>-Djava.ext.dirs=${com.sun.aas.javaRoot}/lib/ext${path.separator}${com.sun.aas.javaRoot}/jre/lib/ext${path.separator}${com.sun.aas.instanceRoot}/lib/ext${path.separator}${com.sun.aas.derbyRoot}/lib</jvm-options>
<jvm-options>-Djdbc.drivers=org.apache.derby.jdbc.ClientDriver</jvm-options>
<jvm-options>-Djavax.management.builder.initial=com.sun.enterprise.admin.server.core.jmx.AppServerMBeanServerBuilder</jvm-options>
<jvm-options>-Dcom.sun.enterprise.config.config_environment_factory_class=com.sun.enterprise.config.serverbeans.AppserverConfigEnvironmentFactory</jvm-options>
<jvm-options>-Dcom.sun.enterprise.taglibs=appserv-jstl.jar,jsf-impl.jar</jvm-options>
<jvm-options>-Dcom.sun.enterprise.taglisteners=jsf-impl.jar</jvm-options>
<jvm-options>-XX:NewRatio=2</jvm-options>