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Posted to common-user@hadoop.apache.org by Todd Lipcon <to...@cloudera.com> on 2009/05/06 22:23:53 UTC

Re: I can see only two mappers per node regardless of mapred.map.tasks value

On Wed, May 6, 2009 at 1:10 PM, Seunghwa Kang <s....@gatech.edu> wrote:

> Hello,
>
> I am running compute intensive job using Hadoop Streaming (hadoop
> version 0.19.1), and my mapper input has several thousand small files.
> My system has 4 nodes and 8 cores per node.
>
> I want to run 8 mappers per node to use all 8 cores, but whatever the
> mapred.map.tasks value is, I can see only two mappers per node (when I
> check it using ps -ef|grep mapper_name).
>
> Any suggestions?
>

Set mapred.tasktracker.map.tasks.maximum and
mapred.tasktracker.reduce.tasks.maximum to your desired values

-Todd