Modified: hadoop/core/trunk/src/docs/src/documentation/content/xdocs/cluster_setup.xml URL: http://svn.apache.org/viewvc/hadoop/core/trunk/src/docs/src/documentation/content/xdocs/cluster_setup.xml?rev=668612&r1=668611&r2=668612&view=diff ============================================================================== --- hadoop/core/trunk/src/docs/src/documentation/content/xdocs/cluster_setup.xml (original) +++ hadoop/core/trunk/src/docs/src/documentation/content/xdocs/cluster_setup.xml Tue Jun 17 03:46:42 2008 @@ -118,6 +118,25 @@ <code>JAVA_HOME</code> so that it is correctly defined on each remote node.</p> + <p>Administrators can configure individual daemons using the + configuration options <code>HADOOP_*_OPTS</code>. Various options + available are shown below in the table. </p> + <table> + <tr><th>Daemon</th><th>Configure Options</th></tr> + <tr><td>NameNode</td><td>HADOOP_NAMENODE_OPTS</td></tr> + <tr><td>DataNode</td><td>HADOOP_DATANODE_OPTS</td></tr> + <tr><td>SecondaryNamenode</td> + <td>HADOOP_SECONDARYNAMENODE_OPTS</td></tr> + <tr><td>JobTracker</td><td>HADOOP_JOBTRACKER_OPTS</td></tr> + <tr><td>TaskTracker</td><td>HADOOP_TASKTRACKER_OPTS</td></tr> + </table> + + <p> For example, To configure Namenode to use parallelGC, the + following statement should be added in <code>hadoop-env.sh</code> : + <br/><code> + export HADOOP_NAMENODE_OPTS="-XX:+UseParallelGC ${HADOOP_NAMENODE_OPTS}" + </code><br/></p> + <p>Other useful configuration parameters that you can customize include:</p> <ul> @@ -128,7 +147,9 @@ </li> <li> <code>HADOOP_HEAPSIZE</code> - The maximum amount of heapsize - to use, in MB e.g. <code>2000MB</code>. + to use, in MB e.g. <code>1000MB</code>. This is used to + configure the heap size for the hadoop daemon. By default, + the value is <code>1000MB</code>. </li> </ul> </section> @@ -335,7 +356,7 @@ <tr> <td>mapred.child.java.opts</td> <td>-Xmx1024M</td> - <td></td> + <td>Larger heap-size for child jvms of maps/reduces.</td> </tr> </table> </li>
Modified: hadoop/core/trunk/src/docs/src/documentation/content/xdocs/mapred_tutorial.xml URL: http://svn.apache.org/viewvc/hadoop/core/trunk/src/docs/src/documentation/content/xdocs/mapred_tutorial.xml?rev=668612&r1=668611&r2=668612&view=diff ============================================================================== --- hadoop/core/trunk/src/docs/src/documentation/content/xdocs/mapred_tutorial.xml (original) +++ hadoop/core/trunk/src/docs/src/documentation/content/xdocs/mapred_tutorial.xml Tue Jun 17 03:46:42 2008 @@ -1066,7 +1066,17 @@ </p> <p>Users/admins can also specify the maximum virtual memory - of the launched child-task using <code>mapred.child.ulimit</code>.</p> + of the launched child-task using <code>mapred.child.ulimit</code>. + The value for <code>mapred.child.ulimit</code> should be specified + in kilo bytes (KB). And also the value must be greater than + or equal to the -Xmx passed to JavaVM, else the VM might not start. + </p> + + <p>Note: <code>mapred.child.java.opts</code> are used only for + configuring the launched child tasks from task tracker. Configuring + the memory options for daemons is documented in + <a href="cluster_setup.html#Configuring+the+Environment+of+the+Hadoop+Daemons"> + cluster_setup.html </a></p> <p>The task tracker has local directory, <code> ${mapred.local.dir}/taskTracker/</code> to create localized
