PHP Warning: exec() unable to fork

Question

So here is a little background info on my setup. Running Centos with apache and php 5.2.17. I have a website that lists products from many different retailers websites. I

Answer 1

In my case (large PHPUnit test suite) it would say unable to fork once the process hit 57% memory usage. So, one more thing to watch for, it may not be a process limit but rather memory.