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From Raghu Angadi <rang...@yahoo-inc.com>
Subject Re: How to split the hdfs in different subgroups
Date Sat, 23 Feb 2008 01:54:07 GMT
xavier.quintuna@orange-ftgroup.com wrote:
> I read the docs about rack awareness but my issue is how the client can
> pick some specific datanodes, which are located in some specific rack,
> to write the block there. The idea is that the client is able to write
> the block in two separated groups of datanodes in the same hdfs. For
> instance: bin/hadoop dfs -put <localpath> <dfspath> -location <rackid>

If you have just 2 racks, and replication of 2 or more, client will 
write at least one replica in each rack. And while reading, client will 
read the replica in located in its rack.

Currently you cannot explicitly control which rack reach replica goes.


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