This will take place ~24 hours from now. Feel free to post and upvote questions beforehand in this post, as it will turn into the AMA tomorrow.
This is a chance for any users, admins, or developers to ask anything they’d like to myself, @[email protected] , SleeplessOne , or @[email protected] about Lemmy, its future, and wider issues about the social media landscape today.
Regarding server architecture - How many users can the Lemmy network, or the fediverse as a total scale to, assuming the average person posts once per day and reads ~50 comments/posts a day?
Lemmy supports horizontal scaling, so in theory it is only limited by the amount of servers you can afford. Of course there are always unpredictable bottlenecks which need to be fixed, but no inherent limitation.
The ActivityPub protocol lemmy uses is (in my opinion) really bad wrt scalability. For example, if you press one upvote, your instance has to make 3000 HTTP requests (one to every instance that cares).
But on the other hand, I recently rewrote the federation queue. Looking at reddit, it has around 100 actions per second. The new queue should be able to handle that amount of requests, and PostgreSQL can handle it (the incoming side) as well.
The problem right now is more that people running instances don’t have infinite money, so even if you could in theory host hundreds of millions of users most instances are limited by having a budget of 10-100$ per month.
In the future it could make sense to make a protocol extension to send multiple activities in a single HTTP connection. But for now its probably not worth the effort, considering that it would break compatibility with other Fediverse platforms.