Writing to HDFS could only be replicated to 0 nodes instead of minReplication (=1)

Question

I have 3 data nodes running, while running a job i am getting the following given below error ,

java.io.IOException: File /user/ashsshar/olhcache/load

Answer 1

I had this problem and I solved it as bellow:

1. Find where are your datanode and namenode metadata/data saved; if you cannot find it, simply do this command on mac to find it (there are located in a folder called "tmp")

   find /usr/local/Cellar/ -name "tmp";

   find command is like this: find <"directory"> -name <"any string clue for that directory or file">

2. After finding that file, cd into it. /usr/local/Cellar//hadoop/hdfs/tmp

   then cd to dfs

   then using -ls command see that data and name directories are located there.

3. Using remove command, remove them both:

   rm -R data . and rm -R name

4. Go to bin folder and end everything if you already have not done it:

   sbin/end-dfs.sh

5. Exit from the server or localhost.

6. Log into the server again: ssh <"server name">

7. start the dfs:

   sbin/start-dfs.sh

8. Format the namenode for being sure:

   bin/hdfs namenode -format

9. you can now use hdfs commands to upload your data into dfs and run MapReduce jobs.