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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.



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