The former, I use #hdfs dfs -ls and I can see the directory "/user"
(and that's why I cannot use "hdfs dfs -mkdir" to create a new one) ~t On Tue, Oct 7, 2014 at 9:06 PM, Azuryy Yu <[email protected]> wrote: > To make sure your dfs.namenode.name.dir is by default. > then, how did you find /user exists? hdfs dfs -ls ? or you checked > dfs.datanode.data.dir? > if the latter, then don't worry. > > > On Wed, Oct 8, 2014 at 11:56 AM, Tianyin Xu <[email protected]> wrote: > >> 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 >> > > -- Tianyin XU, http://cseweb.ucsd.edu/~tixu/
