Hi Mike, On Wed, Aug 29, 2012 at 7:40 AM, Mike S <mikesam...@gmail.com> wrote: > 1> Can I change the heap size for the job tracker only if I am using > version 1.0.2?
Yes. > 2> If so, would you please say what exact line I should put in the > hadoop-evv.sh and where ? Should I set the value with a number or use > the Xmx notion? > > I mean which one is the correct way > > export HADOOP_HEAPSIZE=2000 > > or > > export HADOOP_HEAPSIZE="-Xmx2000m" The above (first one is right syntax) changes the heap across _all_ daemons, not just JT specifically. So you don't want to do that. You may instead find and change the below line in hadoop-env.sh to the following: export HADOOP_JOBTRACKER_OPTS="$HADOOP_JOBTRACKER_OPTS -Xmx2g" > 3> Do I need to restart the job tracker node or call start-mapred.sh > to make the heap size change to take in effect? Is there anything else > I need to do to make the change to be applied? You will need to restart the JobTracker JVM for the new heap limit to get used. You can run "hadoop-daemon.sh stop jobtracker" followed by "hadoop-daemon.sh start jobtracker" to restart just the JobTracker daemon (run the command on the JT node). -- Harsh J
