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HDFS >> mail # user >> namenode grows overtime

felix gao 2012-01-18, 23:23
Koji Noguchi 2012-01-18, 23:39
felix gao 2012-01-20, 01:12
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RE: namenode grows overtime
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



From: felix gao [[EMAIL PROTECTED]]
Sent: Friday, January 20, 2012 6:42 AM
Subject: Re: namenode grows overtime


There is no Java options specified other than -Xmx24g, what are some of the recommended options for namenode?



On Wed, Jan 18, 2012 at 3:39 PM, Koji Noguchi <[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>> 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
from jmap histo outputs, try passing    -XX:-CMSConcurrentMTEnabled .

Background: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7113118

On 1/18/12 3:23 PM, "felix gao" <[EMAIL PROTECTED]<http://[EMAIL PROTECTED]>> 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.


Koji Noguchi 2012-01-20, 19:57
Harsh J 2012-01-19, 02:56
felix gao 2012-01-20, 01:09