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From Devaraj k <devara...@huawei.com>
Subject RE: intermediate results files
Date Tue, 02 Jul 2013 06:00:17 GMT
If you are 100% sure that all the node data nodes are available and healthy for that period
of time, you can choose the replication factor as 1 or <3.

Thanks
Devaraj k

From: John Lilley [mailto:john.lilley@redpoint.net]
Sent: 02 July 2013 04:40
To: user@hadoop.apache.org
Subject: RE: intermediate results files

I've seen some benchmarks where replication=1 runs at about 50MB/sec and replication=3 runs
at about 33MB/sec, but I can't seem to find that now.
John

From: Mohammad Tariq [mailto:dontariq@gmail.com]
Sent: Monday, July 01, 2013 5:03 PM
To: user@hadoop.apache.org<mailto:user@hadoop.apache.org>
Subject: Re: intermediate results files

Hello John,

      IMHO, it doesn't matter. Your job will write the result just once. Replica creation
is handled at the HDFS layer so it has nothing to with your job. Your job will still be writing
at the same speed.

Warm Regards,
Tariq
cloudfront.blogspot.com<http://cloudfront.blogspot.com>

On Tue, Jul 2, 2013 at 4:16 AM, John Lilley <john.lilley@redpoint.net<mailto:john.lilley@redpoint.net>>
wrote:
If my reducers are going to create results that are temporary in nature (consumed by the next
processing stage) is it recommended to use a replication factor <3 to improve performance?
Thanks
john



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