First of all, we're not interested in the file cache at all for the time being, its the user cache that is important.
We need to store information about database structures and query results in a cache for some applications we are developing.
Our server has dozens of sites on it, some of which are controlled by customers with ftp access.
I'm worried about a virtual host (one where we don't control the php files) screwing with the cache of another virtual host. We can code our applications so that their cache keys don't collide, but we can't garuntee that a customer won't clear or modify our cached values.
We have mod_php on a CentOS 5.3 server with plesk. We have
apc.filters="-/.*" as it having it on seems to break a lot of third party apps we have installed.
php_admin_flag apc.enabled off and
php_admin_value apc.enabled 0 in the vhost, but it seems to have no effect.
Is there any way to completely disable apc for some sites only?
Alternatively, is there any way to have a seperate user cache per vhost? Or a different caching solution? We're considering memcached but I worry that it will have similar problems.