PHP

Opcode Cache

Zend OPcache is preferred. Other opcode caches are/were:

• eAccelerator
• APC
• XCache

And they conflict with each other, so check:

php -m | grep -i -E "eaccelerator|apc|xcache|zend"

PHP handlers that can use opcache: DSO (mod_php), FCGI, PHP-FPM

PHP handlers that cannot use opcache: CGI, SuPHP