Isso parece ter feito o truque ...
http {
limit_conn_zone $binary_remote_addr zone=default_con:20m;
limit_req_zone $binary_remote_addr zone=php:1m rate=2r/s;
location ~ \.php {
## LIMIT REQUESTS TO STOP SERVER GETTING NAILED ##
limit_req zone=php burst=7 nodelay;
limit_conn default_con 2;
fastcgi_index index.php;
try_files $uri = 404;
include fastcgi_params;
fastcgi_split_path_info ^(.+.php)(.*)$;
fastcgi_pass unix:/dev/shm/php-fpm-www.sock;
fastcgi_intercept_errors on;
fastcgi_ignore_client_abort off;
}
}