My takeaway from this is maybe somewhat different from what the authors intended:

> The last one? Our friend, cassandra-messages. [...] To start with, it’s a big cluster. With trillions of messages and nearly 200 nodes, any migration was going to be an involved effort.

To me, that's a surprisingly small amount of nodes for message storage, given the size of discord. I had honestly expected a much more intricate architecture, engineered towards quick scalability, involving a lot more moving parts. I'm sure the complexity is higher than stated in the article, but it makes me wonder, given that I've been partially responsible for more than 200 physical nodes that did less, how much of modern cloud architecture is over engineered.