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From Uma Maheswara Rao G <mahesw...@huawei.com>
Subject RE: Re: how to select the position of a block
Date Wed, 07 Dec 2011 17:11:18 GMT

 It has re-factored in trunk.
You can find this in BlockPlacementPolicy ( interface) implementation class. i.e BlockPlacementPolicyDefault.

From: Praveen Sripati [praveensripati@gmail.com]
Sent: Wednesday, December 07, 2011 10:28 PM
To: common-dev@hadoop.apache.org
Subject: Re: Re: how to select the position of a block

Not sure why, but I was able to find ReplicationTargetChooser.java only in
branch-1.0 and not in trunk, 21, 22 and 23.


2011/12/7 郭冲 <guochonghenu@126.com>

> isGoodTarget() in  ReplicationTargetChooser.java  judge if a node is a
> good node, it will consider the disk space , load , and the rack which it
> located has too much nodes or not .Thanks!
> At 2011-12-07 13:01:26,"Harsh J" <harsh@cloudera.com> wrote:
> >Moving discussion to hdfs-dev.
> >
> >DataNodes report disk usage (space) and current transfer thread counts
> (load) periodically to the NameNode. NameNode uses this information to make
> a decision while building the pipeline DNs for your client request. I
> believe the class is called something like ReplicationTargetChooser (off
> the top of my mind), and you can take a look at the logic involved there in
> selecting any form of node (isGoodTarget or summat). Then work your way
> downwards to see how the information flows.
> >
> >On 07-Dec-2011, at 8:36 AM, 郭冲 wrote:
> >
> >> Hadoop:The Definitive Guide  said that when the client is out of the
> cluster, hadoop will select the storage position of a block randomly,but it
> will not select the datanode which is too busy or too full.
> >>
> >> so i want to kown that  how hadoop judge or measure a datanode is full
> or not?
> >

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