I think this feature will help keep communities alive if something goes wrong. I hope Lemmy implements this feature.

  • tunetardis@lemmy.ca
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    1 year ago

    Ok, I’m new here and my understanding is on shaky ground.

    That said, I was under the impression that when you subscribe to a community on another instance, it sort of does get cloned to your own? But everything still has to sync through the master instance somehow. If that were to go down, your locally cached copy would presumably be orphaned, and I’m not really sure what happens at that point? Could it be made into the new master somehow?

    • Grimpen@lemmy.ca
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      1 year ago

      I think it’s more or less as you describe. I think what OP is suggesting would be more like a way to migrate a community. Export everything from !example@oldserver.ded and import everything to !example@newserver.liv

      I think something like this exists for Mastodon users, but I’ve never played with it. You could use this to migrate communities from an instance that was going down or otherwise no longer suitable. Even if all old conversations are “frozen” or locked, it would still be useful upon occasion.

      • Jamie@jamie.moe
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        1 year ago

        Could probably be doable with database fuckery. Make a second community locally with an identical name, then in the backend swap some IDs around and make it think the posts were actually in the new one all along.

        Granted, I haven’t looked at the DB structure, so I don’t know how plausible it is. If someone tries it, don’t blame me if the instance breaks, do at your own risk.

      • Czele@lemmy.world
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        1 year ago

        But that creates a problem with potential duplicate name, but there is even bigger problem. By export I assume You mean taking ownership so adopting this community into the new server, who decides that? First come first served does not look good in my eyes as a good solution. Since that community is stored as a copy in other instances it should maybe just go into read only mode for eternity

    • EndOfLine@lemmy.world
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      1 year ago

      You understand correctly. Migrating an instance would involve updating the source of truth to a different instance, and somehow notifying all other instances to stop checking the old instance and start checking the new.

      Maybe ActivityPub (the protocol the Fediverse is built on) already has a method for assigning redirects, but I would have so many questions. What happens to instances that are experiencing an outage during the migration? What happens with blocked instances if that block is removed after the migration? How long would the redirect notice live? What if a new community with the same name is created on the original instance? What happens to old links pointing to the old instance? Personally, implementing such a feature sounds like a huge headache.

      As for what happens to an an instance once it is orphaned (say the instance with the “true” community blocks another instance or goes dark), then the orphaned copies will become little islands that are only accessible to members on the orphaned instance and any comments, votes, etc are no longer shared across the Fediverse.