You could also mount a folder from that storage drive to a folder you have configured as an FTP-account....
Don't forget to fix that in /etc/fstab
If I need to do this myself I always need to lookup all the exact commands as I don't need it that often.
You can come up with very powerful solutions with these mounts.
I don't have any servers anymore where I use such tricks...
Another trick is using a symbolic link.
I'm doing something similar...
The back-up of one Plesk server is going to another Plesk server and vice versa....
If I would merely setup a normal FTP-account I would soon run into problems as the back-up would be sent to the source server again as it would get backed up itself.
The backup-size would grow exponentially as the complete back-up of that other server would be added to the next back-up.
That's why I created an FTP-account to a folder inside a domain account called "ftpdumps".
After that I removed the folder and replaced it with a symbolic link
ln -s /var/ftpdumps /var/www/vhosts/plesk4.wolf.com/ftpdumps
ls -altr /var/www/vhosts/plesk4.wolf.com/
Code:
total 20K
drwxr-x--- 5 ns4 psaserv 4.0K Mar 16 2017 httpdocs
drwxr-xr-x 2 ns4 psacln 4.0K Mar 16 2017 error_docs
lrwxrwxrwx 1 root root 13 Mar 16 2017 ftpdumps -> /var/ftpdumps
drwx--x--- 5 ns4 psaserv 4.0K Mar 16 2017 .
drwx------ 2 ns4 root 4.0K Jan 3 04:35 logs
drwxr-xr-x 132 root root 4.0K Jan 3 11:25 ..