It is a low level cache mechanism used by Zend to reduce CPU usage on each request through the intermediate code generated by the standard Zend runtime compiler in the Zend Optimizer. A product that improves for faster operation. If you are using php 5.5 on your server and you have not turned it off, you can use this extension. Unlike other cache solutions, APC, Opcache, Memcached, XCache, Varnish, Opcache improves PHP performance by saving pre-compiled script byte code to shared memory, so PHP doesn’t need to load and parse scripts at every request. Opcache configurations available in a Turkish document
If you want to use Opcache, Memcache and Varnish in 3, here is a detailed document. Optache stores PHP’s parsed byte code into memory and goes out of Memory -> CPU -> output when execution is needed. The downside may not be a great solution to a forum (phpBB), if you modify PHP files the cache becomes invalid. Opcache is a clear success, and it seems logical to use it for VPS or similar cloud servers.
Php scripting language creator Rasmus Ledorf has a status monitoring application that can be downloaded from Github Script.
For installation on Linux;
Or this script has made this work completely visual feast I strongly recommend you try this script Responsive coded and looks great on mobile.