A message comes in: a website is not responding. Or rather, it responds but it crawls.
It is a WordPress with a few plugins, all in good shape.
I log in and the load is near zero, traffic is tiny. I start digging and nothing makes sense. I run the command "w" and the machine is frozen.
Nothing in the logs.
Then the light bulb goes on:
"ping bsd.cafe"
No resolution.
The provider’s upstream DNS servers (set in a hurry, I normally install a local unbound) are not responding and everything grinds to a halt. I switch the DNS servers and everything magically starts working again.
Of course it was DNS! 🙂