Well well 🤨

Wats0ns@sh.itjust.works to Selfhosted@lemmy.world – 1331 points –
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Yes they can be on any instance, but I'm starting to get worried about the number of communities that are on Lemmy.world

Why is that worrying?

It disregards the benefits of a distributed platform. Imagine if the admins went rouge, or the server data was irreversibly lost, suddenly all that content would be gone or under the authoritarian rule of the admins. Bit dramatic but you get the point.

If the majority of content is on there, we've quite literally taken a decentralised system and centralised it lol

On a more technical level, it takes quite some ressources for a server to broadcast their communities to all other lemmy instances.

"Receiving" a remote community is just reading data and inserting it in your instance. But if a community is hosted on your instance, you have to send that data to each and every instances with at least one user subscribed to it.

So it's really better for everyone to spread out on as many instances as possible. The only thing I would recommend before setting up a community (or your user account) on an instance is to check if you align with their moderation rules/code of conduct.

We did it reddit err... sorry guys... old habits and all

No. I think the other instances would need to purge that content right? I could be wrong.

Assuming it’s federated. And someone from your server is subscribed to that community.

Communities are inherently tied to the instance on which they are created and cannot be moved. If the instance is overloaded then that community will not federate properly. If the instance goes down nobody can post to the community. If the instance goes away that community goes away (except for the "cache" that other instances have).

Hmm. I’m not sure if that’s the case. I’m interested to see what the plan is for account migration. Weather posts will follow the user. Or stay with the instance.

Migration of ActivityPub stuff is pretty rough... Everything has an ID, and that ID is the URL, so the ID of the post you replied to is literally https://lemmy.nrd.li/comment/227095... AFAIK there are some (non-standard, at least not in core AP) ways you can mark things to be like "yeah, this moved to over here", but that isn't built in to the spec so whether those mechanisms actually work is a crapshoot.

Looking at my sql databases, I noticed there’s other identifiers on users and content. Not the url.

It may be that the url is linked to the ID. And that ID can just change.

I’m pretty much a noob. Just a lurker on the matrix chats.

I'm talking purely from an ActivityPub/Activity Streams/Activity Vocabulary/JSON-LD perspective. There are some other local identifiers for things in Lemmy, but those do not matter for the purposes of federation. Any Object that is federated is expected to have an ID that is a URL at which you can make a GET request with the proper Accept header and you will get the latest version of that Object. AFAIK there is no provision for IDs to change.

Understood. I don’t know how the devs intend to overcome that challenge. If if it’s even a realistic goal. I just know it gets discussed often.

I think we should expect/aim to just have some "mass repost script" that can take an extract of a community's content and just "repost" it on a new community.

Basically, a script that would "replay" a community in one go. I don't know if you could create "new comments" that immitates perfectly the original commenter but that would be the idea for a quick and very dirty "community mover script".

A bit like in GIT when you want to change/remove a specific commit, you can only replay/rebuild everything from the start by creating new everything posts/comments.

Or maybe that's a terrible plan ;)

When lemmy.world will disappear, that'll be a lot of communities (and valuable information) that go with it.

I don’t know if that’s the intention of Lemmy. It’s not Reddit. It’s not an encyclopaedia.

But I get that it would be annoying.

My understanding is that other instances would need to purge Lemmy.works for that info to all disappear.