Performance overhead with COPY command while bulk data loading

Hello Team,

We are facing performance overhead with COPY utility of cql while doing bulk loading of data.

It took approximately 6 hours while loading around 39L records through COPY command.

 Please be noted that there are few frozen types used in the table structure which contains around 15 sets each.

so, please let us know the techniques of optimization to achieve faster loading of data, And also suggest if any parameters can be reset to increase the efficiency.

Your prompt response on this would be highly appreciated

 Thank you,

Nikhil