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From Andy Isaacson <...@cloudera.com>
Subject Re: A question about the namenode's decision on the data placement of a new file
Date Fri, 24 Aug 2012 23:03:42 GMT
On Fri, Aug 24, 2012 at 3:33 PM, wei xu <sqlxweiwei@gmail.com> wrote:
> I am doing some research on the data placement, but I am not quite familiar
> with the Hadoop, is there any one who can tell me when a new file be added
> into the HDFS, which function will be called by namenode to make a decision
> on the allocation ( I mean, if there has a list of datanodes and the file
> might be larger than 64MB, that is, several blocks may be included. What's
> the function that decide the placement of those blocks to those datanode?)

You'll want to read BlockPlacementPolicy and its inheritors.

-andy

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