Hi,

   We are using Jboss AS 5.1 where every instance has 12 wars but getting "java.lang.OutOfMemoryError: PermGen space". errors sporadically,which may result from GC activities.

To resolve the issues, we have the following questions:

1. What's the maximum number of web applications(wars) one jboss instance can support?
2. any recommendation for pergem size settings to support multiple apps,current setting is -XX:MaxPermSize=256m.  It sounds like modern JVM provides more options such as -XX:+CMSClassUnloadingEnabled, should the setting be helpful?

for example something like this?

-XX:PermSize=512m -XX:MaxPermSize=1024 -XX:+UseConcMarkSweepGC -XX:+CMSPermGenSweepingEnabled -XX:+CMSClassUnloadingEnabled

any suggestions will be greatly appreciated

Thanks

-Vic

Here is the JVM and JAVA OPTs settings:

JVM version:  1.60_24 Hotspot 64-bit server

JAVA_OPTS:

-Dprogram.name=startServer.sh -server -javaagent:/opt/wily/8.2.3/Agent.jar -Dcom.wily.introscope.agentProfile=/opt/wily/8.2.3/IntroscopeAgent.profile -Dcom.wily.introscope.agent.agentName=appserver_cm1 -Dub.jvmroute.node=node1 -Dub.deployScanEnable=false -Dub.ajp.maxThreads=150 -Dub.ajp.minSpareThreads=25 -Dub.ajp.maxSpareThreads=25 -Dub.ajp.acceptCount=100 -Dub.ajp.connectionTimeout=600000 -Djboss.messaging.ServerPeerID=1 -Djboss.default.jgroups.stack=ub_tcp -Djboss.jgroups.tcp.tcp_port=7600 -Djboss.jgroups.tcp.tcpping.initial_hosts=10.151.220.49[7600],10.151.200.37[7600] -Dub.db.connectString=jdbc:oracle:thin:@server:port:tnsName -Dub.oracle.db.user= -Dub.oracle.db.pass= -Xms1303m -Xmx1303m -XX:MaxPermSize=256m -Dorg.jboss.resolver.warning=true -Dsun.rmi.dgc.client.gcInterval=3600000 -Dsun.rmi.dgc.server.gcInterval=3600000 -Dsun.lang.ClassLoader.allowArraySyntax=true -Djava.net.preferIPv4Stack=true -Djava.library.path=/opt/jboss-5.1.0.GA/native/lib64::/ora01/oracle/product/11.1.0/lib