Let’s use lemmygrad.ml as an example. My home instance is lemmy.world, which I see has defederated from lemmygrad.ml. If I post to a community on lemmygrad.ml, will everyone be able to see it?
What if the opposite is true? What if lemmygrad.ml is the one who defederated from lemmy.world, and not the other way around as in the above example?
I’m just a little confused by how federation works. I know that I won’t see lemmygrad.ml posts on my All feed due to defederation, regardless of who defederates with whom.
I too am curious about this. Does each instance have its own copy of the data from the other instances? How does it stay in sync?
Each instance has a copy. There are a couple of ways to backfill information, but in general any communication that happens gets broadcast out to every instance that’s subscribed. If an instance is offline or otherwise unavailable (like it’s defederated), then that instance will not get that message and will be slightly out of sync. It’s this semi-sync nature that also makes it so that anything posted likely exists somewhere even after you delete because nothing guarantees that every instance will get the delete message.