On Jun 20, 2011, at 12:24 PM, <praveen.pe...@nokia.com> <praveen.pe...@nokia.com> wrote:
> Hi there, > I know client can send "mapred.reduce.tasks" to specify no. of reduce tasks > and hadoop honours it but "mapred.map.tasks" is not honoured by Hadoop. Is > there any way to control number of map tasks? What I noticed is that Hadoop > is choosing too many mappers and there is an extra overhead being added due > to this. For example, when I have only 10 map tasks, my job finishes faster > than when Hadoop chooses 191 map tasks. I have 5 slave cluster and 10 tasks > can run in parallel. I want to set both map and reduce tasks to be 10 for max > efficiency. http://wiki.apache.org/hadoop/FAQ#How_do_I_limit_.28or_increase.29_the_number_of_concurrent_tasks_a_job_may_have_running_total_at_a_time.3F
