Installation of Varnish caching server in Redhat/CentOS/Fedora Varnish will significantly improve your website performance as it responses static pages from cache. After installation of Varnish, for same number of simultaneous requests less requests go to your web server as many of them will be served by Varnish. So, you can consider your web server simultaneous
Getting real client IP through Varnish After installation Varnish as frontend caching server your Web server ( like Apache, Nginx etc.) and application (PHP, ASP, JSP etc.) will not see real client IP from which request is coming. Rather than they will see client IP as 127.0.0.1 if Varnish and Web server are installed in
Apache is a powerful, reliable and capable web server. The single biggest hardware issue affecting Apache webserver performance is RAM. In Linux by default Apache use Prefork MPM which is memory intensive module. So, server with less memory struggles if requests increase. Addressing the issue, many server experts suggest two things Replace Apache by Nginx