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From James Teng <tenglinx...@outlook.com>
Subject RE: How to recover reducer task data on a different data node?
Date Thu, 03 Jul 2014 09:59:44 GMT
Hi, thanks for your quick reply.could you pls explain bit more in details? like how to get
the info which map nodes have to transfer data to this new reducer node. and how to communicate
with them to transfer the data here.or via what kind of way to copy data. 
Date: Thu, 3 Jul 2014 16:52:57 +0800
Subject: Re: How to recover reducer task data on a different data node?
From: sshi@gopivotal.com
To: user@hadoop.apache.org

It will start from scratch to copy all map outputs from all mapper nodes; Regards,Stanley

On Thu, Jul 3, 2014 at 2:28 PM, James Teng <tenglinxiao@outlook.com> wrote:

First i would like to declare that although i am not new to hadoop, but not expert on it as
well.i would like to consult one issue on mapreduce framework. below is the description of
the scenarios.

When one reduce task is failed on one datanode, then the job tracker will try to schedule
another node to set up this reduce job and  continue running, my question is how to get the
assigned data back on the new node? when the map phase is done, the output data will be copied
to the respective partitioned reducer, now if the reduce is created on the a new node, what
kind of actions does the new node take to get all the map-allocated data back.

thanks in advance.

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