My home instance is shutting down soon.
https://lemm.ee/post/65824884.
I am slightly unclear about what the instance admin meant.
Because of how Lemmy is built, everything posted on lemm.ee will still be accessible from other instances, even after we go offline.
How are other Lemmy instance able to access the content from the post-shutdown lemm.ee?
Do all the other Lemmy instances keep a copy of the content from lemm.ee?
If so, wouldn’t that be rather taxing on each Lemmy instance? (since they have to keep a copy of all the content from all instances they federate with).
I tried reading this up by researching on Lemmy federation, but this is still unclear to me.
Do all the other Lemmy instances keep a copy of the content from lemm.ee?
Yes, but it only keeps text and links, any images uploaded to lemm.ee will be lost. Any community in lemm.ee will still be visible but nobody outside of your instance will see anything you post there so they’re effectively dead.
nobody outside of your instance will see anything you post there
So you are saying that if let’s say a user from
lemmy.worldmakes a post to the post-shutdownlemm.eecommunity, only users withinlemmy.worldcan see the content? Did I understand that correctly? Basically each instance has a "copy of lemm.ee's community, andlemm.ee` is acting as the main distributor of events between these “isolated communities”.Is there any indication for the
lemmy.worldpeople to notice that the instance hosting the community is gone? Wouldn’t there be cases where users continue posting to a community who’s instances have shutdown, without realizing that they are not visible outside?Exactly, yes.
Is there any indication for the lemmy.world people to notice that the instance hosting the community is gone?
I don’t think there is but I remember the lemmy devs saying they’ll add a warning at some point when a community can’t be reached.
Federation means that when anything happens on one instance (post, comment, whatever), that instance will also inform other instances of this. Which other instances? The ones that have at least one user who has indicated they are interested in that kind of activity (on Lemmy mostly: by subscribing to the community).
So already now you can see eg my instance’s copy of a lemm.ee community at https://discuss.tchncs.de/c/cartographyanarchy@lemm.ee and this will not disappear just because lemm.ee goes down. It’s stored in my instance’s database. But it will no longer be possible to post or comment there because that will no longer federate to other instances.
It’s not guaranteed that all of lemm.ee will be accessible elsewhere. Some communities might not have (always had) subscribers from other instances, which would mean no other database has stored those parts.
To shreds
The way ActivityPub federation works, once an instance is “linked” (like lemm.ee linking with lemmy.world, lemdro.id, etc), the instance will now send them an event once a post is made or something like that.
For example:
- lemm.ee —links–> lemmy.world
- lemm.ee user makes a post A
- lemm.ee —notifies–> lemmy.world
- lemmy.world makes a copy of post A.
So yes, every Lemmy instance stores copies of new data from other instances once they link.
every Lemmy instance stores copies of new data
What about the old data? Are they also stored retroactively once the link happens?
And about the linking, from what I gather, (taking your example) as long as any one user from
lemmy.worldfrom retrieves posts fromlemm.ee, or if they subscribe to it, the “link” will happen. Is that correct?Is there anyway to verify that the data is persisted on
lemmy.world? As long as the post/community is visible right now fromlemmy.world, would it be indication that it will be there even afterlemm.eeshuts down?Basically, I am mainly concerned whether my previous content on
lemm.eewill be persisted.When instances federate, they don’t send old content. Old content will be fetched if a user tries to open it, for example by clicking a link to an old post (on some apps) or pasting its url into the search box.
The data copied to the other instance will stay on the other instance, unless manually deleted for some reason.
So if a brand new instance is started, it does not retroactively receive any content from other servers. Only ones that were connected by a link at the time content was posted will have a copy, essentially.
To know which posts will be kept on different servers, look up your own username, e.g. https://lemmy.ca/u/TrivialKin@lemm.ee
Will images uploaded to lemm.ee be federated with the other Lemmy servers, or will they be permanently deleted?
I’ve heard conflicting answers to this question, and I’d like to get a definite answer.
afaik those get deleted. However there shouldn’t be many images uploaded to that server specifically because the instance admins were really hesitant about ever opening image uploads much. They often advocated for using another 3rd party for image hosting.
It’s conflicting because it depends™. By default Lemmy is configured to mirror images by remote instances so as to not overwhelm them with traffic. But most instances turn that off because of the storage cost.
