Question : Apache as a Proxy

I need to build in some sort of redundancy for my web server, running Apache 2.2, Mysql and PHP 5. What I'm looking to do is essentially have 2 servers, a main server and then a "live backup" server to step in if the load gets too big on the main server.

Is this something that Apache's proxy capabilities can do? Is the mysql replication feature the way to go with db synchronization? Do I need a third machine to "direct traffic" ?

Answer : Apache as a Proxy

Possibly the best solution would be to setup a Squid proxy server setup using round robin as a front end server and then have two 'web servers' for handling the web requests. If your web site is more MySQL driven than static HTML pages, then you might want to look at setting up a MySQL cluster or a master/master replication setup.

What operating system are you using for hosting the sites and databases on?

If you were using something like RHEL 5, you could setup Global File System (GFS) across two to three web servers (for distributing the load). Another alternative is to setup the 'backup' web server with NFS mounts to the master server for handing the /web/ directories, etc.