Hi, I wanna run some experiments on Hadoop which requires a clean, initial system state of HDFS for every job execution, i.e., the HDFS should be formatted and contain nothing.
I keep *dfs.datanode.data.dir* and *dfs.namenode.name.dir* the default, which are located in /tmp Every time before running a job, 1. I first delete dfs.datanode.data.dir and dfs.namenode.name.dir #rm -Rf /tmp/hadoop-tianyin* 2. Then I format the nameNode #bin/hdfs namenode -format 3. Start HDFS sbin/start-dfs.sh 4. However, I still find the previous metadata (e.g., the directory I previously created) in HDFS, for example, #bin/hdfs dfs -mkdir /user mkdir: `/user': File exists Could anyone tell me what I missed or misunderstood? Why I can still see the old data after both physically delete the directories and reformat the HDFS nameNode? Thanks a lot for your help! Tianyin
