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From Harold Lim <rold...@yahoo.com>
Subject Re: Question about HDFS Architecture
Date Fri, 21 Aug 2009 13:42:19 GMT
> Also, if a file has multiple replicas stored on multiple
> datanodes on the same "rack", how does the
> namenode pick which datanode the client has to talk to? In
> this case, all datanodes are homogeneous, which makes the
> "rack-awareness" unimportant to the decision
> making.
> I believe the datanode itself picks. In the absence of rack
> information, it's choice is random (unless one is
> localhost, in which case that one gets used). 

Hi Aaron,

Did you mean the client itself picks? So the namenode simply gives the list of datanode that
has the file, and the client picks from this list?



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