An simple script to fill your disk with random file.

random.sh

#!/bin/bash
for i in {1..7}
do
  for i in {1..100}
  do
      openssl rand -out "$i.random" -base64 2147483647
      if [ $? -ne 0 ]; then
        echo "Disk full, do clean"
        rm -rf *.random
        break;
      fi
  done
done