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The following page has been changed by Arun C Murthy: http://wiki.apache.org/lucene-hadoop/FAQ The comment on the change is: Added a section on how to control maximum concurrent tasks on a tasktracker ------------------------------------------------------------------------------ Learn more about safe mode [http://lucene.apache.org/hadoop/api/org/apache/hadoop/dfs/NameNode.html#setSafeMode(org.apache.hadoop.dfs.FSConstants.SafeModeAction) here]. + + [[BR]] + [[Anchor(13)]] + '''13. [#13 I see a maximum of 2 maps/reduces spawned on each TaskTracker, how do I increase that?]''' + + Use the configuration knob: [http://lucene.apache.org/hadoop/hadoop-default.html#mapred.tasktracker.tasks.maximum mapred.tasktracker.tasks.maximum] to control the number of maps/reduces spawned simultaneously on a !TaskTracker. By default, it is set to ''2''. + + Caveats: + * ''mapred.tasktracker.tasks.maximum'' that is a cluster-wide limit i.e. controlled at the !JobTracker end. [http://issues.apache.org/jira/browse/HADOOP-1245 HADOOP-1245] should fix that. + * ''mapred.tasktracker.tasks.maximum'' controls the number of maps '''and''' number of reduces. [http://issues.apache.org/jira/browse/HADOOP-1274 HADOOP-1274] should fix that. +
