how can i get large files to do experimentation

I finished creating the first spark application. In order to know its performance i need large files (.csv) to do some tests and experimentation to monitor my application in order to tune it.

We all know that the size of data has a serious impact on results, but all files.csv that i have are small, so i can not trust or confirm results that i get.

How can i get files with large size? help me please

I need large sizes such:

 10 GB, 20 GB, 30 GB, 50 GB, 100 GB, 300 GB, 500 GB.....