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HDFS, mail # user - Waiting long for the DataNode to be ready


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Re: Waiting long for the DataNode to be ready
Harsh J 2012-02-13, 23:32
Hao,

This only affects your startup, and once its up you should have no
further issues, and was fixed via
https://issues.apache.org/jira/browse/HDFS-1835.

This was also previously discussed at http://search-hadoop.com/m/0n3W12wbQRQ

As a workaround, you can try adding inside conf/hadoop-env.sh:

export HADOOP_OPTS="$HADOOP_OPTS -Djava.security.egd=file:/dev/./urandom"

On Tue, Feb 14, 2012 at 4:51 AM, Hao Lin <[EMAIL PROTECTED]> wrote:
> Hi,
>
> I am beginning with Hadoop. I have been experiencing a trouble of waiting a
> long time before I can add (put) my input data to HDFS in Hadoop v0.20.2.
>
> I followed configuration step and format the HDFS. I am able to create new
> directory but when I am try to add input data set to DFS, I am stuck by a
> very common error:
>
>   "java.io.IOException: File ... could only be replicated to 0 nodes,
> instead of 1"
>
> then I use command "hadoop dfsadmin -report", and it says there is 0
> available datanode.
>
> Usually, I wait for another 5 or 10 minutes and then datanode is ready and I
> can continue to put on the data file. So is there a way that I could avoid
> waiting for the 5 minutes? I mean it happens also in the pseudo-cluster
> mode.
>
> Thanks.
>
> --
> best wishes
>
> Hao Lin (林昊)
> Research Assistant
> School of Electrcial & Computer Eng
> Purdue University, West Lafayette, IN
> Personal Homepage: http://web.ics.purdue.edu/~lin116/
>

--
Harsh J
Customer Ops. Engineer
Cloudera | http://tiny.cloudera.com/about