Hi Felix, Taking jmap –histo:live <pid> would tell you what’s occupying the heap.
Are you using UseConcMarkSweepGC? If yes, and if you see bunch of java.net.SocksSocketImpl sun.nio.ch.SocketChannelImpl from jmap histo outputs, try passing -XX:-CMSConcurrentMTEnabled . Background: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7113118 Koji On 1/18/12 3:23 PM, "felix gao" <gre1...@gmail.com> wrote: Hi guys, we are running Hadoop 0.20.2+228, the namenode process's memory grows overtime to occupy over 18GB. However, if I restart the namenode, it only occupies about 10GB after it is stable. I am wondering if there is anyway to figure out what is going on with namenode that causes it to grow very rapidly and if there are any tools to make the namenode printout some useful information on what is holding onto that memory. Thanks, Felix
