I wondered how much resources (network data, disk space) a #fedi instance would consume depending on the number of users, so I made a simple model.

tl;dr: the main issue with hosting a fediverse instance is the amount of data it sends on the network, which grows almost as the square of the number of users.

https://github.com/wimvanderbauwhede/limited-systems/wiki/A-simple-model-for-network-data-size-and-disk-space-usage-of-a-fediverse-instance