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From sridhar basam <...@basam.org>
Subject Re: controlling no. of mapper tasks
Date Mon, 20 Jun 2011 20:36:39 GMT
On Mon, Jun 20, 2011 at 4:13 PM, <praveen.peddi@nokia.com> wrote:

> Hi David,
> Thanks for the response. I didn't specify anything for no. of concurrent
> mappers but I do see that it shows as 10 on 50030 (for 5 node cluster). So I
> believe hadoop is defaulting to no. of cores in the cluster which is 10.
> That is why I want to choose the map tasks also same as no. of cores so that
> they match with max concurrent map tasks.
>
>
The maximum number of simultaneous mappers and reducers across the cluster
are determined by your config. You are seeing capacity as 10 mappers since
you probably have a default mapred-site.xml file. The default max jobs per
task tracker is 2.

http://hadoop.apache.org/common/docs/r0.20.0/mapred-default.html

Sridhar

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