Lemmy Support

Hi, I’m new to the fediverse and trying to wrap my head around lemmy specifically.

If i’m signed into an account on beehaw.org and post to a community on lemmy.ml, is my post/comment saves on beehaw.org or lemmy.ml’s server? I understand that it will be federated between both servers but I’m curious which database the post lives i’m. Or is it replicated across both.

And do other federated services work the same way, like mastodon?

Thanks for the help in understanding this stuff!