/etc/nginx/nginx.conf
fastcgi_cache_path /tmp/nginx_cache levels=1:2 keys_zone=MYAPP:6000m  inactive=720m;
fastcgi_cache_key $scheme$request_method$host$request_uri;
default.server.conf
set $skip_cache 1;
if ($request_uri ~* "^/i/[0-9]+$" ) {
    set $skip_cache 0;
}
location ~ .php {
    fastcgi_pass 127.0.0.1:9008;
    include      fastcgi_params;
     
    fastcgi_param SCRIPT_FILENAME $document_root/index.php;
    fastcgi_param SCRIPT_NAME /index.php;
    fastcgi_param PATH_INFO $request_uri;
    fastcgi_cache MYAPP;
    fastcgi_cache_valid 200 40m;
    fastcgi_ignore_headers  Expires ;
    fastcgi_cache_bypass $skip_cache; 
    fastcgi_no_cache $skip_cache;
    add_header X-nx-Cache "$upstream_cache_status - $upstream_response_time";
}