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From EdwardKing <zhan...@neusoft.com>
Subject question about hadoop dfs
Date Sun, 26 Jan 2014 06:22:21 GMT
I use Hadoop2.2.0 to create a master node and a sub node,like follows:

Live Datanodes : 2
Node  Transferring Address  Last Contact  Admin State  Configured Capacity (GB)  Used(GB)
 Non DFS Used (GB)  Remaining(GB)  Used(%)  
master         1                In Service           16.15             
                0.00              2.76                        13.39                 0.00
node1         0                 In Service           16.15             
               0.00               2.75                        13.40                 0.00

Then I create a abc.txt file on master
[hadoop@master ~]$ pwd
[hadoop@master ~]$ echo "This is a test." >> abc.txt
[hadoop@master ~]$ hadoop dfs -copyFromLocal test.txt
[hadoop@master ~]$ hadoop dfs -ls
DEPRECATED: Use of this script to execute hdfs command is deprecated.
Instead use the hdfs command for it.

14/01/25 22:07:00 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your
platform... using builtin-java classes where applicable
Found 1 items
-rw-r--r--   2 hadoop supergroup         16 2014-01-25 21:36 abc.txt

[hadoop@master ~]$ rm abc.txt
[hadoop@master ~]$ hadoop dfs -cat abc.txt
This is a test.

My question is:
1. Is supergroup a directory?  Where does it locate?
2. I search abc.txt on master and node1 by following command:
[hadoop@master ~]$ find / -name abc.txt 
But I don't find abc.txt file. Where is the file abc.txt? After I erase it by rm command,
I still cat this file? Where is it? My OS is CentOS-5.8.

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