On occasion my 2CPU 4GB Digital Ocean droplet struggles to cope with the volume of traffic to my customer websites. I have around 40 separate sites for my customers, each using a Wordpress website. All sites are using 'ondemand' PHP-FPM Process Manager with 10 PHP-FPM pm.max_children and 10 second PHP-FPM pm.process_idle_timeout. All are on PHP7 using PHP-FPM. All sites utilise the CloudFlare free membership plan. All sites also use W3TotalCache plugin. Most have LetsEncrypt certificates and all use MySQL (installed on the same box). When many sites are hit at the same time the box can quickly hit a load of 15-20 and everything slows down. I'm wondering what to look at next to improve performance of the droplet. Or whether I should be considering moving certain things to another droplet. Any suggestions? Thanks, Nick
How much memory is used on that setup? If the host is short on memory, using cache on Worpress may make things slower. I assume disk system is fast on that thing?
Memory is generally not the issue. It's CPU that is maxed out. I'm not sure I follow you regarding Wordpress Caching. How can using caching slow things down? If pages are compiled into HTML then they are static pages and don't need any processing by PHP and no hit on SQL.
Wordpress is not the most ressource-friendly cms ;-) Most installations I have seen have unnecessary plugins and additional components. Google insights can tell you about stuff which could be improved: https://developers.google.com/speed/pagespeed/insights/ If not already done, activate http2 (Is more to increase speed, does not necessarily reduce load ) If you know, that you have heavy duty websites, consider to use static php_fpm (if, as you said ram is not the issue). However, I wouldn't run 40 active websites with 4GB Ram. https://haydenjames.io/php-fpm-tuning-using-pm-static-max-performance/
