https://www.cnblogs.com/mylovelulu/p/9516727.html
<property>
<name>dfs.datanode.data.dir</name>
<value>/data/hadoop/data</value>
</property>
<!--namenode dir default dir :/usr/local/hadoop-2.7.3/tmp/dfs/name/current
<property>
<name>dfs.namenode.name.dir</name>
<value>/data/hadoop/namenode_dir</value>
</property>
-->