So you can’t afford a F5 load balancer? But your Apache server is dying under the load?
We had to use load balancing using DNS because we had scaling issues. Fast and good fix (just add a box and one line of code).
Create different DNS entries for different front side Apache servers:
www1.example.com
www2.example.com
www3.example.com
And in your code (PHP):
$baserUrl = "www".rand(1,3).".example.com";