I'm running a LAMP box with PHP running as fcgid. APC is installed and working well. However, each PHP process gets its own cache. This is a problem, because it would make far more sense to have 10 PHP processes with 300MB shared APC cache than 10 PHP processes, each with a redundant 30MB unshared APC cache.
There was a prior thread on this topic 8 months ago (How to share APC cache between several PHP processes when running under FastCGI?) and I am wondering if there have been any developments in this realm since then.
As far as I know it's still not possible to use shared memory cache with any PHP cacher amongst multiple processes... anyway, unless you're under extremely heavy load you should be fine with separate caches, I suppose, since they'll be filled pretty quickly. And hey, RAM is cheap nowadays!