The documentation on php.net is very spotty about causes of failure for APC writes. What kind of scenarios would cause a call to apc_store() to fail?
There's plenty of disk space available, and the failures are spotty. Sometimes the store operation will succeed and sometimes it'll fail.
For php cli it needs to be enabled with another option: apc.enable_cli=On
In my situation it was working when running from a webbrowser, but not when executing the same stuff with php cli.
http://php.net/manual/en/apc.configuration.php
the apc.ttl and apc.user_ttl settings on php.ini:
Leaving this at zero means that APC's cache could potentially fill up with stale entries while newer entries won't be cached.
