FastCgi cache query for multiple seperate WordPress websites

Hi,

Im setting up multiple stand alone instances of Wordpress on a single Ubuntu Server with LEMP.

Each individual wordpress website will have its own install and db

This guide states that the top 4 lines need to go into the main nginx conf file.

#move next 4 lines to /etc/nginx/nginx.conf if you want to use fastcgi_cache across many sites fastcgi_cache_path /var/run/nginx-cache levels=1:2 keys_zone=WORDPRESS:100m inactive=60m; fastcgi_cache_key “$scheme$request_method$host$request_uri”; fastcgi_cache_use_stale error timeout invalid_header http_500; fastcgi_ignore_headers Cache-Control Expires Set-Cookie;

The top line has me confused though…each keys_zone value has to be unique as i understand?

How can i make each keys_zone value unique if it has to have 1 value in th emain nginx file and not in each websites nginx server block file?

Other guides say that just the cache-key line needs moving to the main nginx file?

Ive setup a cache folder in each websites directory path for the cahed files for that website.

Should i be creating just 1 super cache folder and storing all websites cache files in there rather than a cache folder for each individual website?

Can somebody clarify with me the best way to setup caching for multiple sites please - not using multisite though!

Thanks in advance