[btasker]

> most CDNs will send every single request in that period through.

I don't think this is true. It certainly isn't for any CDN that I've worked for or on.

Cloudflare don't do this either - they use a cache lock - the first request basically acts as a blocker for all the others, leaving the other requests waiting for the response (if it's cacheable they serve that response, if not then they proceed to origin).

It's normally configurable, but most sane CDNs do have it enabled by default, precisely because big bursts tend to be sharp in nature and a cache miss can be origin breaking at that point.

Just for completeness's sake, Nginx's HTTP proxy module can do it too (the setting's proxy_cache_lock) though it is off by default there.