I have 2 different VPS, both KVM-based, sysinfo is identical on both, and I have identical website on both.
When using proxy_fcgi_event one of the servers has no issues, but the other server have directory permission errors. On that server, if I set certain directory permissions to 777 there are no issues.
When I swithch both servers to php-fpm_event mode then domain error log shows [FastCGI: neither POLLIN nor POLLOUT...] [mydomain.com] at regular intervals on both servers.
With this error, do you thin that the response time will slow down significatly if there are many logged in to the domain at the same time ?