How can I determine if a name changer has been molded?

Question

When I first set up my namenode, I know that I need to run

bin/hadoop namenode -format 

but running it a second time after loading the data into HDFS, wipe everything off and reformat it. Is there an easy way to find out if a namenode has been formatted?

Answer 1

Well, you can check this file store1 / name / current / VERSION

If it exists, it is already formatted.

PS: You format only once in a lifetime in a production system. It is best done during installation or manually in disaster recovery mode.