Server - Out of memory Killed process (HTTPD)
 

What would cause a linux server to run out of memory and become *virtually* unresponsive except to pings ?

A reboot has been fixing this.. until a couple days later.

most likely you've killed/aren't running the pdflush demon/your memory management is fuct up.

maybe a script causing a memory leak / not freeing up resources?

Yes, basically any program which leaks memory can cause this - at some point you'll run out of memory and the kernel will start killing things that want memory.

For instance your httpd.

If you run top for a while you might find which program(s) are hogging your memory.