Depends. I’m subscribed to about 80 communities on various servers and my server is receiving about one federation post every second. The database has grown to about 2GB in size over the past two weeks for 1,977,387 registered activities. I’m guessing traffic will be similar.

Lemmy will clean up posts older than six months. You can probably write a quick and dirty script to purge content better (i.e. purge all but the most recent oldest 100k posts from each server) and run that every night or so.

RAM requirements are about 300MiB for Lemmy, and whatever you pick for Postgres. User post storage depends on what your users upload. CPU usage is rather minimal.

I would love to hear the answer to this as well. I guess it’s heavily dependent on how many users you have and if they are uploading images or just text, or just lurking.

I think if you did not allow signups it would probably be extremely minimal.

I suspect that it depends on if you’re accepting other users and or communities. If so, you’ll have to be global mod and probably spend time sorting out mod reports etc.

If you’re just setting up an instance for yourself, it’s probably easier but you’ll need an account somewhere else to discover communities and index them back to your instance.

Honestly, I’m interested in knowing some of this too.

https://join-lemmy.org/docs/en/administration/administration.html says about 150GB RAM and negligible CPU usage.

I assume an instance with users subscribed to active communities requires meaningful storage, but I’m not clear the sizes we’re talking about (what’s data growth per/day been like for some of the larger communities).

EDIT: Likewise, I’d love to know if that 150GB RAM is fixed or whether that number grows with use.