and I thought watching baseball games on server traffic graphs was nerdy

Manual pages (from anyone) are 50% bullshit and 50% the scariest possible page, and the worst part is that it often takes a few minutes to determine which one it is

Request coalescing or whatever you call it is a table stakes feature for CDNs and also gives CDN engineers nightmares. It has horribly complex interactions with everything.

I'm a little surprised that Cloudflare doesn't hedge. Maybe the involvement of Concurrent Streaming Acceleration is that it prevents hedging? The post doesn't say this but I could see it. Or maybe they do and the network was just that bad, but I'd expect it to affect more than one fill in that case.

The thundering herd comes from the 'every client waits on a single SIN to IAD fill' behavior, which my team calls "request coalescing", not sure what Cloudflare calls it but it's clear from blog.cloudflare.com/introducing-... that it's an optimization on top of coalescing, not coalescing itself.

Interesting read! It's a little weird to blame the behavior on Concurrent Streaming Acceleration: they'd probably get the same behavior if clients other than the first waited for the full asset before starting to download it, assuming that it's js so it's fairly small.