The short answer is… not by much. WordPress relies on, as scribu (a guy who started by writing very clever and useful plugins, such as Posts 2 Posts, WP CLI, Plugin Dependencies and many many others, ending up in the WP core team for a while) put it: crappy language (PHP, an ancient version to … Read more
There is a very nice plugin called P3 (Plugin Performance Profiler). Give it a try! This plugin creates a profile of your WordPress site’s plugins’ performance by measuring their impact on your site’s load time. Often times, WordPress sites load slowly because of poorly configured plugins or because there are so many of them. By … Read more
It’s not likely an unused site is using mach resources except for harddrive space. There may be something left in memory but on a typical server thats doubtfull. google bots trigger the site exactly the same as a regular user except it doesnt load unnessasary files like javascript, css or images (except maybe for image … Read more
Need to set both the constants before ABSPATH is defined. Right after this line in wp-config.php define( ‘WP_DEBUG_LOG’, true );
@IlmarsL: thanks! I really did not think of that. I had the plugin Query Monitor enabled and this was the problem… Turning Query Monitor off solved the problem and memory did no more longer increase.
wp-config.php sets the memory limit for the specific WordPress site which has that file. php.ini will effect your whole server. The php.ini is the parent setting, and so you can set WP to whatever you want within php.ini‘s range. It’s also importan to note there is a WP_MAX_MEMORY_LIMIT where you can define a max amount … Read more
The actual RAM you need depends on many factors: plugins theme installed extensions (server and PHP) the current operation (editing images needs the most) translation, some translation files are really heavy In a multisite, some resources are shared, the server setup for example is not duplicated each time you create a new site. You can … Read more
The WordPress Memory is something not easy to deal with. If the standard way is not helping (don’t rely on the WP_MEMORY_LIMIT constant, it’s conceptually broken, use ini_set in wp-config.php instead), then you can only throw hardware on it or hack the core. Please check if you’re using a recent PHP version on your system. … Read more
It’s hard to answer this given that each site is most likely different and each server is also configured differently. If these sites are individual WordPress installs then 1GB /30 sites is normal, an absolute bare minimum per site would be 32MB for apc.shm_size, this equals 960MB with no overhead. 32MB is in my opinion … Read more
Ater months of searching I stubmled upon this https://bugs.php.net/bug.php?id=72451 The bug is resolved in PHP 7.1.