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From: centerqi hu <centerqi@gmail.com>
Date: Sun, 7 Oct 2012 23:28:55 +0800
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 <CA+RDP1k5KqcGmt3t=PHcqvRQK7vh7Lo7jfYqcQvky=qoTo5ALg@mail.gmail.com>
Subject: Re: What is the difference between Rack-local map tasks and
 Data-local map tasks?
To: user@hadoop.apache.org
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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=EF=BC=9F

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=3D124
> Data-local map tasks=3D6
>
> What is the difference between Rack-local map tasks and Data-local map
> tasks?
> --
> centerqi@gmail.com|Sam
>
>
>


--=20
centerqi@gmail.com|=E9=BD=90=E5=BF=A0

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Very good explanation,<div>If there is a way to reduce=C2=A0Rack-local map =
tasks=C2=A0</div><div>but can increase the=C2=A0Data-local map tasks=C2=A0,=
</div><div>Whether to increase performance=EF=BC=9F<br><br><div class=3D"gm=
ail_quote">2012/10/7 Michael Segel <span dir=3D"ltr">&lt;<a href=3D"mailto:=
michael_segel@hotmail.com" target=3D"_blank">michael_segel@hotmail.com</a>&=
gt;</span><br>

<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex"><div style=3D"word-wrap:break-word">Rack loc=
al means that while the data isn&#39;t local to the node running the task, =
it is still on the same rack.=C2=A0<div>

(Its meaningless unless you&#39;ve set up rack awareness because all of the=
 machines are on the default rack. )</div><div><br></div><div>Data local me=
ans that the task is running local to the machine that contains the actual =
data.=C2=A0</div>

<div><br></div><div>HTH</div><div><br></div><div>-Mike</div><div><div class=
=3D"h5"><div><br><div><div>On Oct 7, 2012, at 8:56 AM, centerqi hu &lt;<a h=
ref=3D"mailto:centerqi@gmail.com" target=3D"_blank">centerqi@gmail.com</a>&=
gt; wrote:</div>

<br><blockquote type=3D"cite"><br clear=3D"all"><div>hi all</div><div><div>=
<p>When I run &quot;hadoop job -status xxx&quot;,Output the following some =
list.</p>

<pre><code>Rack-local map tasks=3D124
Data-local map tasks=3D6
</code></pre><p>What is the difference between Rack-local map tasks and  Da=
ta-local map tasks?</p></div></div>-- <br><a href=3D"mailto:centerqi@gmail.=
com" target=3D"_blank">centerqi@gmail.com</a>|Sam<br>
</blockquote></div><br></div></div></div></div></blockquote></div><br><br c=
lear=3D"all"><div><br></div>-- <br><a href=3D"mailto:centerqi@gmail.com" ta=
rget=3D"_blank">centerqi@gmail.com</a>|=E9=BD=90=E5=BF=A0<br>
</div>

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