[fxtentacle]

If the underlying hardware is a bare metal server, it won't magically turn slow and have a CPU spike. That problem is caused noisy neighbor and kind of exclusive to clouds.

Well, with the 2x example, my app might get from a 1s P99 to a 2s P99 which feels slow, but is still doable. Again, those timeouts are usually introduced by cloud infrastructure. For example, if you use nginx outside of Heroku, it won't have a 30s timeout for file downloads.

[ses1984]

Your own instances can have an unexpected CPU spike.

Even if you're running on bare metal I find it hard to believe you don't have a layer with short timeouts between your front and backend.

[fxtentacle]

Why would I? I have redundant 1GBit LAN cables between front end, back end, and database servers.

[ses1984]

Because it's bad ux for your users to see a spinning loading icon forever.

[fxtentacle]

And a timeout error would be better?

[ses1984]

In my experience, yes, a lot better.