Apache – Can’t upload >2GB file

I believe what you need to be looking at is the retry option that you can pass with the ProxyPass directive.

retry default: 60 seconds

Connection pool worker retry timeout in seconds. If the connection pool worker to the backend server is in the error state, Apache will not forward any requests to that server until the timeout expires. This enables to shut down the backend server for maintenance, and bring it back online later. A value of 0 means always retry workers in an error state with no timeout.

It appears you have the dreaded Persistent Bush Syndrome (PBS for short)....which means you are stuck with way too many W's (sending reply). Luckily, there's is a very simple fix. The cause may be that your script is performing a long winded query that never completes. Check out this article, it explains how to fix diagnosis and track down the cause of connections stuck in "sending reply" status http://techmythsworld.blogspot.com/2011/11/solving-httpd-maxclients-and-modstatus.html

In short, you need to do the following: 1. Find the script that is getting stuck in W's and whatever is being posted to it (it might be very unique variables that cause it to get stuck.

2. Ensure that you can recreate the situation by posting the causing variables to the script. You will see a connection show up from your ipaddress that will remain stuck in W.

3. Track down if you have an loop or a database query that doesn't end.

4. Fix the script. and repost the variables, you should see that the stuck in W for your ipaddress is gone.

PS. You must restart the webserver with every test to reset your connection (command "service httpd restart" should do