Saving files to another partition with PHP or Symbolic Link?

We have a PHP based application running on a cPanel server which saves tons of API log files (millions), and we are looking to have the PHP scripts be able to write the API log text files into another partition (Amazon EFS mounted to server), so that we can more easily move those text files around. The df-h output is below:

7.3G     0  7.3G   0% /dev
tmpfs           7.3G     0  7.3G   0% /dev/shm
tmpfs           7.3G  115M  7.2G   2% /run
tmpfs           7.3G     0  7.3G   0% /sys/fs/cgroup
/dev/xvda1      1.5T  623G  828G  43% /
/dev/loop0      3.9G  8.3M  3.7G   1% /tmp
127.0.0.1:/     8.0E  609G  8.0E   1% /smartefs01
tmpfs           1.5G     0  1.5G   0% /run/user/0
tmpfs           1.5G     0  1.5G   0% /run/user/1005

The drive that we want to save the files to is located in /smartefs01, the actual PHP application resides in /home/user/public_html . We are struggling to find the easiest way to have the PHP application store files in /smartefs01 instead of /home/user_public_html. Since we want to be able to detach the drive and move it around with all the files on it in cases of changing servers etc. Let me know your thoughts! Kind regards, EC