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From Elaine Gan <>
Subject Re: Number of MR running mahout kmeans
Date Mon, 03 Dec 2012 09:42:14 GMT
Dear Owen,

Thank you.

> This isn't specific to Mahout. In Hadoop, your capacity has no bearing
> on how many jobs Hadoop chooses to run. The ".maximum" properties are
> just expressing how many tasks to run concurrently on one worker.
> Hadoop will always run 1 reducer unless you tell it otherwise with
> mapred.reduce.tasks. I think most of the jobs don't try to set this
> for you and you'll have to do so yourself.

No wonder i see only 1 reducer no matter how many times i tried to
execute it.
Thank you!

> The number of maps depends on the size and number of input files. I
> wouldn't override it, but, if you must you can do so by decreasing the
> maximum split size that one mapper takes.



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