How to use block storage for existing website without delete/moving it to the block storage?

How to use block storage for existing website without delete/moving it to the block storage? my /dev/sda1 is now full, I attach a new volume like 50GB, and it already mouted in /mnt/volume… I’m using easyengine nginx to host my website. My website is located at /var/www/example.com/htdocs, and I want to use my block storage to save my wp-content that located in /var/www/example.com/htdocs/wp-content. so It will saved in block storage… what should I do? I’ve try this Link

I try this

mkdir /mnt/volume.../wp-content
sudo chown -R www-data:www-data /mnt/volume.../wp-content

and edit /etc/nginx/sites-enabled/default and add this to the last line

        location /wp-content/ {
                alias /mnt/volume.../wp-content/;
        }

after that, I save it, and restart nginx service, and it got error serverctl1… can you help me how to implement this?