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From centerqi hu <cente...@gmail.com>
Subject Re: What is the difference between Rack-local map tasks and Data-local map tasks?
Date Sun, 07 Oct 2012 15:28:55 GMT
Very good explanation,
If there is a way to reduce Rack-local map tasks
but can increase the Data-local map tasks ,
Whether to increase performance?

2012/10/7 Michael Segel <michael_segel@hotmail.com>

> Rack local means that while the data isn't local to the node running the
> task, it is still on the same rack.
> (Its meaningless unless you've set up rack awareness because all of the
> machines are on the default rack. )
>
> Data local means that the task is running local to the machine that
> contains the actual data.
>
> HTH
>
> -Mike
>
> On Oct 7, 2012, at 8:56 AM, centerqi hu <centerqi@gmail.com> wrote:
>
>
> hi all
>
> When I run "hadoop job -status xxx",Output the following some list.
>
> Rack-local map tasks=124
> Data-local map tasks=6
>
> What is the difference between Rack-local map tasks and Data-local map
> tasks?
> --
> centerqi@gmail.com|Sam
>
>
>


-- 
centerqi@gmail.com|齐忠

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