So.. Interesting problem for you guys, As I'm completely lost as to what to do, or where to take the next step.

Server & Application Environment.

CentOS release 5.3 (Final)

Apache 2.2.3-22

EnableSendfile off
EnableMMAP off
ErrorLog logs/error_log
LogLevel debug

PHP-5.2.6-2

error_reporting = E_ALL
display_errors = on
log_errors = on
max_execution_time=300
max_input_time=60
memory_limit=512mb

Kohana 2.3 PHP Environment.

HAProxy 1.3.15.6-2

MemCacheD 1.2.6-1

Our application is split between 3 web servers, mounting a NFS Storage server, and sticky load balancing between the 3 web servers. The application seemingly runs great, but every so often, instead of loading, the application just shows a pure white page. Not a 404 Error, or a 500 Server Error, a clean white page. And it returns instantly, so its not a execution time error.

Nothing in the Error log, or Server-Error Log, Proxy log shows standard proxied connection, Just the standard 200-Status in Access log, with 256 bytes transferred.

To me, this leads to tell me that the application itself is having a problem. A rare, unexplainable, seemingly random, problem that causes what we've now called the "White Screen of Death."

Our developers all say that since there is nothing going to our error logs, that it must be a server problem. But I say the same thing, There's nothing going to ANY of our logs (relevent to this anyway), and we're not having httpd children crash from what i can tell.

Any ideas on how i can increase my logs, or somehow prove that its not a bug in PHP, Apache, CentOS, ect? Or if it is somehow a bug, identify it?