Hadoop ERROR datanode DataNode All directories in dfs data dir are invalid

Question

jps shows only Namenode and secondary Namenode. Then I started datanode by

 bin$./hadoop datanode

Then got this error: ERROR datanode.DataNode: Alldirectories in dfs.data.dir are invalid.

Can anyone help out with the solutions to the above error?

Answer 1

Hi,

Try this, first delete all contents from temporary folder:

rm -rf /app/hadoop/tmp/​

Make sure that dir has right owner and permission /app/hadoop/tmp/

bin$sudo chown hduser:hadoop -R /app/hadoop/tmp/

bin$sudo chmod 777 -R /app/hadoop/tmp/

Format the namenode:

bin$./hadoop namenode -format

Start all processes again: 

bin$./start-all.sh​