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From Amal G Jose <amalg...@gmail.com>
Subject Re: Hadoop Installation Mappers setting
Date Thu, 23 May 2013 17:33:46 GMT
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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