Can you please check in UI, what is the heap usage. Then we can confirm whether java heap is growing or not.
top will consider native memory usage also and nio uses directByteBuffers internally. This is good write up from Jonathan https://groups.google.com/group/asynchbase/browse_thread/thread/c45bc7ba788b2357 Regards, Uma ________________________________ From: felix gao [gre1...@gmail.com] Sent: Friday, January 20, 2012 6:42 AM To: hdfs-user@hadoop.apache.org Subject: Re: namenode grows overtime Koji, There is no Java options specified other than -Xmx24g, what are some of the recommended options for namenode? Thanks, Felix On Wed, Jan 18, 2012 at 3:39 PM, Koji Noguchi <knogu...@yahoo-inc.com<mailto:knogu...@yahoo-inc.com>> wrote: 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<http://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
