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From Shahab Yunus <shahab.yu...@gmail.com>
Subject Re: Query regarding the replication factor in hadoop
Date Fri, 19 Sep 2014 12:34:52 GMT
Your write will not succeed. You will get an exception like "xxxx could
only be replicated to 0 nodes, instead of 1"

More details here:
http://www.bigdataplanet.info/2013/10/Hadoop-Tutorial-Part-4-Write-Operations-in-HDFS.html
http://cloudcelebrity.wordpress.com/2013/11/25/handling-hadoop-error-could-only-be-replicated-to-0-nodes-instead-of-1-during-copying-data-to-hdfs-or-with-mapreduce-jobs/
http://wiki.apache.org/hadoop/CouldOnlyBeReplicatedTo


Regards,
Shahab

On Fri, Sep 19, 2014 at 8:16 AM, Raghavendra Chandra <
raghavchandra.learning@gmail.com> wrote:

> Hi All,
>
> I have one very basic query regarding the replication factor in HDFS.
>
> Scenario:
>
> I have 4 node cluster : 3 data nodes and 1 master node.
>
> The replication factor is 3. So ideally each data node would  get one
> replica .
>
> Assume that meanwhile one of the data node went down.
>
> so ideally we will be having 2 data nodes.
>
> Queries:
>
> 1. How hadoop will take care of balancing of replicas as the required
> replicas are 3 , but we have only 2 data nodes up and running.
>
> 2. What happens when we try to write new  data into hdfs at this point of
> time ? whether the write would be successful with only 2 data nodes and
> replication factor 3 or it returns any error message?
>
>
> These queries might be simple, but it would be really helpful if some one
> can answer.
>
> Thanks and regards,
> Raghav Chandra
>
>

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