Okay, so here's a #matrix / #synapse question that I am far too tired to find the answer to:
If i have more than one user on my server, and they both go to a room, do I store duplicates of t hat room, one for each user? Or is it stored on my homeserver in such a way that both can grab it and decrypt it?
When the first user from your server enters the room, your and remote server starts to sync it between each other. If all your users leave, the room is removed from your side after the peroid specified in "forgotten_room_retention_period" config flag.
So no, it is not duplicated for users, just between servers.
Also there is a tool "synadm" that has a command to purge all rooms without local users.
@b4ux1t3 I would also love to know the answer to this.
@SkipfordJ someone answered! https://101010.pl/@didek/114272687101145806