hadoop-hdfs-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From ViSolve Hadoop Support <hadoop.supp...@visolve.com>
Subject Re: Why I cannot delete all the nameNode metadata?
Date Wed, 08 Oct 2014 12:27:04 GMT
Hello,

HDFS default location /user, you can't delete the home directory for 
hdfs. If you create a file or directory, it will be created under /user.

For example: hdfs dfs -mkdir <name>

Regards,
ViSolve Hadoop Support

On 10/8/2014 10:44 AM, Tianyin Xu wrote:
> 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 
> <mailto: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
>     <mailto: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/ <http://cseweb.ucsd.edu/%7Etixu/>


Mime
View raw message