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From Alex Loddengaard <a...@cloudera.com>
Subject Re: More Replication on dfs
Date Fri, 10 Apr 2009 05:20:25 GMT
Did you load any files when replication was set to 3?  If so, you'll have to
rebalance:

<http://hadoop.apache.org/core/docs/r0.19.1/commands_manual.html#balancer>
<http://hadoop.apache.org/core/docs/r0.19.1/hdfs_user_guide.html#Rebalancer>

Note that most people run HDFS with a replication factor of 3.  There have
been cases when clusters running with a replication of 2 discovered new
bugs, because replication is so often set to 3.  That said, if you can do
it, it's probably advisable to run with a replication factor of 3 instead of
2.

Alex

On Thu, Apr 9, 2009 at 9:56 PM, Puri, Aseem <Aseem.Puri@honeywell.com>wrote:

> Hi
>
>            I am a new Hadoop user. I have a small cluster with 3
> Datanodes. In hadoop-site.xml values of dfs.replication property is 2
> but then also it is replicating data on 3 machines.
>
>
>
> Please tell why is it happening?
>
>
>
> Regards,
>
> Aseem Puri
>
>
>
>
>
>

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