How can I tune the PHP realpath cache?

Question

Recent versions of PHP have a cache of filenames for knowing the real path of files, and require_once() and include_once() can take advantage of it

Answer 1

the 16K is the # of files not activity.

Set to 1k for most sites. Very similar to settings in APC, xcache ea etc.

Answer 2

You've probably already found this, but for those who come across this question, you can use realpath_cache_size() and realpath_cache_get() to figure out how much of the realpath cache is being used on your site and tune the settings accordingly.

Answer 3

Though I can't offer anything specific to your situation, my understanding is that 16k is pretty low for most larger PHP applications (particularly ones that use a framework like the Zend Framework). I'd say at least double the cache size if your application uses lots of includes and see where to go from there. You might also want to increase the TTL as long as your directory structure is pretty consistent.