How many connections per minute can result from being on HN frontpage?

I had an app on the frontpage for a whole day last year (Show HN) and the server behaved like a champ... a simple 6US/month, cloud compute instance on Vultr. It was a Rails app as well.

I generally dont understand how some sites go down so quick.

How much traffic was it?

20 GB over 24 hours.

For an unprepared server, a lot.

Nginx 1.18.0 too, oof