HDFS namenode won't start after disk full error

If you have trouble restarting the NameNode in a Hadoop cluster after a disk full error, if you don't mind losing some data, you can do the following to get it back up.

Find the 'edits' file in the hadoop dfs.name.dir/current and write this sequence to it :

printf "\xff\xff\xff\xee\xff" > edits

After that, you should be able to start hadoop. Credit here.