J-M, It should be in the mapred-site.xml the values are mapred.tasktracker.map.tasks.maximum and mapred.tasktracker.reduce.tasks.maximum. This is the default in CDH4
<property> <name>mapreduce.tasktracker.map.tasks.maximum</name> <value>2</value> <description>The maximum number of map tasks that will be run simultaneously by a task tracker. </description> </property> <property> <name>mapreduce.tasktracker.reduce.tasks.maximum</name> <value>2</value> <description>The maximum number of reduce tasks that will be run simultaneously by a task tracker. </description> </property> This would explain why they are going 2 by 2. Does this help? On Thu, Oct 11, 2012 at 4:25 PM, Jean-Marc Spaggiari < [email protected]> wrote: > I don't know. I did not touched that. Where can I found this information? > > 2012/10/11 Kevin O'dell <[email protected]>: > > What are you max tasks set to? > > > > On Thu, Oct 11, 2012 at 3:59 PM, Jean-Marc Spaggiari < > > [email protected]> wrote: > > > >> Hi, > >> > >> Is there a way to force the number of map tasks in a MR? > >> > >> I have a 25 regions table splitted over 6 nodes. But the MR is running > >> the tasks only 2 by 2. > >> > >> Is there a way to force it to run one task on each regionserver > >> serving at least one region? Why is the MR waiting for 2 taskes to > >> complete before sending to the other tasks? > >> > >> I'm starting the MR with a caching of 100. > >> > >> I tried mapred.map.tasks and speculative=false with no success. > >> > >> Any idea how I can increase it this number of tasks? > >> > >> Thanks, > >> > >> JM > >> > > > > > > > > -- > > Kevin O'Dell > > Customer Operations Engineer, Cloudera > -- Kevin O'Dell Customer Operations Engineer, Cloudera
