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From Tianyin Xu <t...@cs.ucsd.edu>
Subject Re: Why I cannot delete all the nameNode metadata?
Date Wed, 08 Oct 2014 05:14:25 GMT
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 <azuryyyu@gmail.com> 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 <tixu@cs.ucsd.edu> 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/

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