Tis page is veing updated at APC Debian
Once you activate APC from PHP.INI, you should probably use some directives to make this magical invention work.
For example, APC and smarty templates don’t go together bery well, SMARTY caches it’s results into PHP files rather than reparsing them, if APC is set not to check for changes in files, it will simply not load the new SMARTY template untill the APC cached version is gone.
But APC is such a beuty, and it translates to lower load on your server.
First, you should understand that on a big PHP server, many changes need to be done.
First, APC data lives in shared memory, By default on a linux system this is usually 33 Megabytes, not enough for one big PHP program, you need to increase it
1- How much shared memory is there now
2- Change that to something suitable
vi /etc/sysctl.conf (Reboot don’t you think )
remember, Don’t go too high, if your system gets low on memory and starts swapping, you are out of luck
3- Make sure you know what the settings here do… what you can change for directories and what you can’t etc..