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From Demai Ni <nid...@gmail.com>
Subject read from a hdfs file on the same host as client
Date Mon, 13 Oct 2014 18:58:33 GMT
hi, folks,

a very simple question, looking forward a couple pointers.

Let's say I have a hdfs file: testfile, which only have one block(256MB),
and the block has a replica on datanode: host1.hdfs.com (the whole hdfs may
have 100 nodes though, and the other 2 replica are available at other
datanode).

If on host1.hdfs.com, I did a "hadoop fs -cat testfile" or a java client to
read the file. Should I assume there won't be any significant data movement
through network?  That is the namenode is smart enough to give me the data
on host1.hdfs.com directly?

thanks

Demai

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