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From Apache Wiki <wikidi...@apache.org>
Subject [Hadoop Wiki] Update of "ZooKeeper/Troubleshooting" by PatrickHunt
Date Fri, 02 Apr 2010 04:58:48 GMT
Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Hadoop Wiki" for change notification.

The "ZooKeeper/Troubleshooting" page has been changed by PatrickHunt.
http://wiki.apache.org/hadoop/ZooKeeper/Troubleshooting?action=diff&rev1=10&rev2=11

--------------------------------------------------

  
  The Java GC can cause [[https://issues.apache.org/jira/browse/HBASE-1316|starvation of the
Java threads]] in the VM. This manifests itself as client disconnects and session expirations
due to starvation of the heartbeat thread. The GC runs, locking out all Java threads from
running.
  
+ You can get an idea of what's happening wrt GC in your client/server VMs by using the following
options when starting the JVM:
+ 
+ -Xloggc:gc.log -XX:+PrintGCApplicationStoppedTime -XX:+PrintGCApplicationConcurrentTime
-XX:+PrintGC -XX:+PrintGCTimeStamps -XX:+PrintGCDetails
+ 
+ Additionally you can use 'jstat' on a running jvm to gain more insight into realtime GC
activity, see: http://java.sun.com/j2se/1.5.0/docs/tooldocs/share/jstat.html
+ 
  This issue can be resolved in a few ways:
  
  First look at using one of the alternative GCs, in particular [[http://developer.amd.com/documentation/articles/pages/4EasyWaystodoJavaGarbageCollectionTuning.aspx|low
latency GC]]:

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