Before I can install MogileFS onto the cluster, I need first to prepare some computer nodes for it. Our cluster has more than 70 nodes, and I’ll use 6 nodes to setup the MogileFS, so, first I need to recommission the 6 nodes from Hadoop.
According to one thread from ServerFault, First, we need to add the following lines to conf/mapred-site.xml,
<property>
<name>dfs.hosts.exclude</name>
<value>/etc/hadoop/conf.dist/dfs.hosts.exclude</value>
<final>true</final>
</property>
where in the value part, we put the name of the file containing the 6 nodes. After this, use?hadoop dfsadmin -refreshNodes to notify HDFS to transfer the data from the 6 nodes and delete the 6 nodes from the system. We can monitor this process from the webpage http://hadoop_master_data_node/dfsnodelist.jsp?whatNodes=LIVE
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