Error after upgrading datastax to version 5
Insufficient permissions on directory /hints


I'm guessing that your "cassandra" user doesn't have permissions to add a new directory on its own.  Similar to the tarball installation process, you'll need to create the directory yourself.


  where the location for this directory?


By default, the location for /hints is:

$CASSANDRA_HOME/data/hints


You can also override this in your cassandra.yaml, with the hints_directory property:

hints_directory: /var/lib/cassandra/hints