In my experience, it's usually the database that gives out first. It's often a shared database, or one running on overprovisioned hardware.
The kinds of sites that go down when receiving unexpected traffic are usually built in such a way where they're making multiple DB requests to render each page. Or they have a dozen poorly configured perf-expensive WordPress plugins running. Or likely all of the above
The kinds of sites that go down when receiving unexpected traffic are usually built in such a way where they're making multiple DB requests to render each page. Or they have a dozen poorly configured perf-expensive WordPress plugins running. Or likely all of the above