JVM settings?

[Mahesh_Vikram]

Hi

can any one explain me in detail for the below lines

CQ_JVM_OPTS='-server -Xmx8192m -XX:MaxPermSize=256M -Xgcpolicy:gencon -Xmn3072m
-verbose:gc -Xverbosegclog:/apps/cq/author/crx-quickstart/logs/gc.log -Djava.awt
.headless=true -Djava.io.tmpdir=/apps/cq/author/temp -Dcom.sun.management.jmxrem
ote -Dcom.sun.management.jmxremote.port=9999 -Dcom.sun.management.jmxremote.auth
enticate=false -Dcom.sun.management.jmxremote.ssl=false -Djackrabbit.maxQueuedEvents=200200000 -Dorg.apache.jackrabbit.core.security.authorization.acl.CachingEn
tryCollector.maxsize=20000'

[Ove_Lindström · Accepted solution]

Yepp... :) All are JVM options or program instructions.

-server = Tells the JVM to start in server mode

-Xmx8192m = Max 8 Gb of heap.

-XX:MaxPermSize=256M = Max 256 Mb of Permanent Generation. Briefly, it contains the Java objects associated with classes and interned strings.

-Xgcpolicy:gencon = What type of garbage collection policy to use.

-Xmn3072m = Nursery memory size when using gencon gc policy.
-verbose:gc = Print what the GC is doing.

-Xverbosegclog:/apps/cq/author/crx-quickstart/logs/gc.log = Print it to this file.

-Djava.awt.headless=true =

-Djava.io.tmpdir=/apps/cq/author/temp = Where is the io temp directory?

-Dcom.sun.management.jmxremote = Allow JMX remote connection

-Dcom.sun.management.jmxremote.port=9999 = to the 9999 port.

-Dcom.sun.management.jmxremote.authenticate=false = and have no authentication (don't try this at home... ;) )

-Dcom.sun.management.jmxremote.ssl=false = and over a non secure connection.

-Djackrabbit.maxQueuedEvents=200200000 = Alow this amount of events to be queued in the JR repo.

-Dorg.apache.jackrabbit.core.security.authorization.acl.CachingEntryCollector.maxsize=20000 = and use a ACL Cache size of 20000 items.

All this params are for performance and monitor tuning.

/Ove