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HDFS, mail # dev - A question about the namenode's decision on the data placement of a new file


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Re: A question about the namenode's decision on the data placement of a new file
Vivi Lang 2012-08-25, 00:00
Thanks but I found that BlockPlacementPolicy only appear after 0.21.0? Is
there any similar class or function appeared in 0.20.
On Fri, Aug 24, 2012 at 6:03 PM, Andy Isaacson <[EMAIL PROTECTED]> wrote:

> On Fri, Aug 24, 2012 at 3:33 PM, wei xu <[EMAIL PROTECTED]> 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
>