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 <CAF4PTbzHMG8PxvBtdHeCi2M0sXkaDO57M8EpkrPa8VvQk9i2ZA@mail.gmail.com>
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Date: Thu, 23 May 2013 23:03:46 +0530
Message-ID: 
 <CAHr4DavHJWzOR3JV2Hc5sBJC4_O7Qx=SoWzsbMM2yp3wLpc5Lw@mail.gmail.com>
Subject: Re: Hadoop Installation Mappers setting
From: Amal G Jose <amalgjos@gmail.com>
To: user@hadoop.apache.org, bejoy.hadoop@gmail.com
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I am explaining it more.
If your machine have 8 GB of memory.
After reserving to Operating system and all other processes except
tasktracker, you have 4 GB remaining(assume).
The remaining process running is tasktracker.
If the child jvm size is 200 MB,
Then you can define a maximum slots of 4*1024 MB/ 200 MB
Which is approximately 20.
You can divide the slots into mapper and reducer slots as per your
requirement.
This is just an example that I explained based on my knowledge.


On Thu, May 23, 2013 at 7:48 PM, <bejoy.hadoop@gmail.com> wrote:

> **
> Hi
>
> I assume the question is on how many slots.
>
> It dependents on
> - the child/task jvm size and the available memory.
> - available number of cores
>
>
>
> Your available memory for tasks is total memory - memory used for OS and
> other services running on your box.
>
> Other services include non hadoop services as well as hadoop daemons.
>
> Divide the available memory with child jvm size and that would get the max
> num of slots.
>
> Also check whether sufficient number of cores are available as well.
>
>
> Regards
> Bejoy KS
>
> Sent from remote device, Please excuse typos
> ------------------------------
> *From: * Jitendra Yadav <jeetuyadav200890@gmail.com>
> *Date: *Thu, 23 May 2013 18:10:38 +0530
> *To: *<user@hadoop.apache.org>
> *ReplyTo: * user@hadoop.apache.org
> *Subject: *Hadoop Installation Mappers setting
>
> Hi,
>
> While installing hadoop cluster, how we can calculate the exact number of
> mappers value.
>
>
> Thanks~
>

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<div dir=3D"ltr">I am explaining it more.<div style>If your machine have 8 =
GB of memory.</div><div style>After reserving to Operating system and all o=
ther processes except tasktracker, you have 4 GB remaining(assume).</div><d=
iv style>
The remaining process running is tasktracker.</div><div style>If the child =
jvm size is 200 MB,</div><div style>Then you can define a maximum slots of =
4*1024 MB/ 200 MB=A0</div><div style>Which is approximately 20.</div><div s=
tyle>
You can divide the slots into mapper and reducer slots as per your requirem=
ent.</div><div style>This is just an example that I explained based on my k=
nowledge.</div><div style><br></div></div><div class=3D"gmail_extra"><br>
<br><div class=3D"gmail_quote">On Thu, May 23, 2013 at 7:48 PM,  <span dir=
=3D"ltr">&lt;<a href=3D"mailto:bejoy.hadoop@gmail.com" target=3D"_blank">be=
joy.hadoop@gmail.com</a>&gt;</span> wrote:<br><blockquote class=3D"gmail_qu=
ote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex=
">
<u></u><div>Hi<br><br>I assume the question is on how many slots.<br><br>It=
 dependents on<br>- the child/task jvm size and the available memory.<br>- =
available number of cores <br><br><br><br>Your available memory for tasks i=
s total memory - memory used for OS and other services running on your box.=
<br>
<br>Other services include non hadoop services as well as hadoop daemons.<b=
r><br> Divide the available memory with child jvm size and that would get t=
he max num of slots.<br><br> Also check whether sufficient number of cores =
are available as well.<br>
<br><br><div>Regards <br>Bejoy KS<br><br>Sent from remote device, Please ex=
cuse typos</div><hr><div><b>From: </b> Jitendra Yadav &lt;<a href=3D"mailto=
:jeetuyadav200890@gmail.com" target=3D"_blank">jeetuyadav200890@gmail.com</=
a>&gt;
</div><div><b>Date: </b>Thu, 23 May 2013 18:10:38 +0530</div><div><b>To: </=
b>&lt;<a href=3D"mailto:user@hadoop.apache.org" target=3D"_blank">user@hado=
op.apache.org</a>&gt;</div><div><b>ReplyTo: </b> <a href=3D"mailto:user@had=
oop.apache.org" target=3D"_blank">user@hadoop.apache.org</a>
</div><div><b>Subject: </b>Hadoop Installation Mappers setting</div><div cl=
ass=3D"im"><div><br></div><div>Hi,</div>
<div>=A0</div>
<div>While installing hadoop cluster, how we can calculate the exact number=
 of mappers value.</div>
<div>=A0</div>
<div>=A0</div>
<div>Thanks~</div>

</div></div></blockquote></div><br></div>

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