This has been driving me crazy all day.
Results for homepage: https://www.webpagetest.org/result/201011_Di4R_847f05a83874173519caaefffb27c297/
Sometimes, the site will work perfectly, returning pages in less than a second. Other times, random static assets will hang for over a minute, the page won’t first byte for 30-60 seconds, or the connection will poop out completely and CloudFlare will pop up a 520 error page.
The site is hosted on a cloud VPS. top shows very low CPU usage, disk space/quota isn’t close to being fully used, and upgrading memory doesn’t seem to affect the issue whatsoever. Site traffic is low and bandwidth isn’t being saturated at all.
Even requesting blank static assets sometimes takes up to 6-10 seconds for TTFB, seemingly at random.