Comment by toast0

> I have been doing this for two decades. Let me tell you about bare metal.

> Back in the day we had 1,000 physical servers to run a large scale web app. 90% of that capacity was used only for two months. So we had to buy 900 servers just to make most of our money over two events in two seasons.

> We also had to have 900 servers because even one beefy machine has bandwidth and latency limits. Your network switch simply can't pump more than a set amount of traffic through its backplane or your NICs, and the OS may have piss-poor packet performance too. Lots of smaller machines allow easier scaling of network load.

I started working with real (bare metal) servers on real internet loads in 2004 and retired in 2019. While there's truth here, there's also missing information. In 2004, all my servers had 100M ethernet, but in 2019, all my new servers had 4x10G ethernet (2x public, 2x private), actually some of them had 6x, but with 2x unconnected, I dunno why. In the meantime, cpu, nics, and operating systems have improved such that if you're not getting line rate for full mtu packets, it's probably becsause your application uses a lot of cpu, or you've hit a pathological case in the OS (which happens, but if you're running 1000 servers, you've probably got someone to debug that).

If you still need 1000 beefy 10G servers, you've got a pretty formidable load, but splitting it up into many more smaller servers is asking for problems of different kinds. Otoh, if your load really scales to 10x for a month, and you're at that scale, cloud economics are going to work for you.

My seasonal loads were maybe 50% more than normal, but usage trends (and development trends) meant that the seasonal peak would become the new normal soon enough; cloud managing the peaks would help a bit, but buying for the peak and keeping it running for the growth was fine. Daily peaks were maybe 2-3x the off-peak usage, 5 or 6 days a week; a tightly managed cloud provisioning could reduce costs here, but probably not enough to compete with having bare metal for the full day.