Raspberry Pi on Raspberry Pi
Since the lack of netboot means we couldn’t just drop the Pi 4 in as a faster version at this time, we went back to the lab and we built an alpha Pi 4 Cloud on a smaller scale: 18 Pi 4s that Raspberry Pi have very generously given to us, all connected with gigabit ethernet so we can try out the 2.5x faster CPUs, 3x faster Network and 4x RAM capacity. The configuration is also only deployed in a single data centre with all servers on a single switch, whereas in normal usage the Raspberry Pi website is simultaneously hosted in two different data centres for redundancy. Once netboot on Pi 4 is available, we’ll be adding 4 core A72 / 4GB servers to our Pi Cloud, at a slightly higher price than the existing Pi 3 servers, reflecting the higher hardware and power costs.
Source: blog.mythic-beasts.com