Correct me if I’m wrong. I read ActivityPub standards and dug a little into lemmy sources to understand how federation works. And I’m a bit disappointed. Every server just has a cache and the ability to fetch something from another known server. So if you start your own instance, there is no profit for the whole network until you have a significant piece of auditory (e.g. private instances or servers with no users). Are there any “balancers” to utilize these empty instances? Should we promote (or create in the first place) a way how to passively help lemmy with such fast growth?
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You are right. On the one hand, it’s kind of bad, naive distributed architecture (my day job), it could have been done much better. On the other hand, the more important point is that it demonstrates an alternative to centralized. We’ll learn a lot about usage patterns here, get new ideas, and either improve Lemmy or build something better from the ground up. Big thanks to Reddit for driving users this way to test scalability and get much better knowledge of usage.
It’s not distributed architecture as you normally think it - it’s a decentralised federation. It’s an important distinction from your typical distributed architecture app.
Can you explain what’s the difference?
A distributed architecture generally refers to a single application or service designed to be resilient to individual data center failures. For example, Reddit, a centralized application controlled by Reddit itself, operates data centers around the world to process user transactions. In the event of an outage in a specific location, such as California, Reddit would still be able to function because its infrastructure for handling user requests and serving data would automatically switch to other functioning data centers elsewhere, like Nevada, Arizona, or Washington. This is an example of a distributed architecture.
On the other hand, a decentralized federation does not consist of a single application. Instead, it involves a software platform like Lemmy, which is hosted on multiple individual hosts. When a user signs up with one host, they can interact with users from other hosts, but each host manages its own infrastructure. For instance, someone could host a Lemmy instance on an old laptop they found in their closet and name it ballsuckers.com, while another person could host a Lemmy instance in the cloud with a properly designed distributed architecture and name it bingbong.com. Each host is responsible for managing its own instance. Users from both instances can interact with each other, but if, for example, the hard drive of ballsuckers.com were to fail, the entire ballsuckers.com instance would go down. However, this would not affect bingbong.com because its infrastructure is separate and managed independently.
I hope this helps!
What makes a distributed system good that Lemmy hasn’t done? Seems like a pretty robust system to me, seems like scaling issues are on the instance host themself. With Reddit’s experience, I don’t see how there are issues
If there was an easy solution that balanced decent UX and performance, we’d have it by now!
it could have been done much better.
Care to expand on this point?
Disclaimer: I’ve only looked a bit at the protocols and high levels descriptions of how it works, and this is just my understanding of it. But it seems to track.
let’s take … [email protected] for example. Right now lemmy.world is the Source of Truth on this, which means if you sign up for it on a different host, let’s say myawersomeinstance.com, that first contacts lemmy.world, copies over posts, and then subscribes on new posts for that. Actually not 100% sure if lemmy.world contacts myawersomeinstance.com when there’s a new post, or myawersomeinstance.com polls lemmy.world… But anyway, point is, lemmy.world is authority on it. myawersomeinstance.com also have [email protected] data, but it’s a copy of it. And lemmy.world is only authority. So if you post something, your server then sends it to lemmy.world and waits a reply. Then lemmy.world contacts all instances that has at least one user following this to tell about the new post. And that new post now exists on a few hundred databases.
The problem is the scaling is whack. Okay, you can have 5000 federated servers with users subscribing to [email protected], but that means lemmy.world needs to update 5000 servers per post, and there’ll be 5000x storage used for that post, and ALL 5000 servers contacts lemmy.world to get the new good stuff.
Frankly, it’s a scaling nightmare. As for a different approach, you could have private / public keys and sign updates from lemmy.world and allow the other instances to fetch the new data from each other. That would also allow more relaxed caching, since it would be generally lower cost to re-fetch the data. Now you need aggressive caching because you don’t want lemmy.world to keel over and die form every server on the planet wanting to hear the latest and greatest posts all the time.
Thanks for the in depth write up! I haven’t looked too far into the docs or the subscription model, but is this a fault on Lemmy’s end, or is this a function of how activity pub handles federated communication? (I’m very new to activity pub/federation, just now reading through the activity pub docs)
I do like your idea of distributed replication via keys,much better than what I had brainstormed
Edit: yeah it does look like it’s a function of activity pub, wonder if theres a more scalable federation protocol out there
Could lemmy.world put a load balancer in front and use that to direct requests to different instances of lemmy.world? Not sure if that question is dumb I’m not a technical guy.
It’s not dumb at all, and it’s a common scaling technique. But the software needs to support it, and I have no idea if lemmy has support for running multiple instances for one server.
I just commented on this in another thread: https://lemmy.world/comment/76011
TL;DR: The server-to-client interactions on Lemmy are a lot heavier than the server-to-server interactions, so even if you’re just using your own server to interact with communities on other servers, it should still take load off of the servers you would have been using directly.
That’s news to me. I thought serverto-server interactions would be heavier since other instances will keep fetching contents from your instance once they start federating. I guess it’s better to join less populated instances instead of crowding on a single instance.
I’ve created my own instance in order to not create more load on others and it took a minute to realise I needed to populate it myself, would be nice to have a default view aggregating popular posts etc. across instances. But maybe I’m just asking for too much hehe
That’s an interesting idea. Maybe you could even choose the “default subs” for your instance from across lemmy.
I did the exact same thing. Ended up looking up the more popular communities on the bigger instances and searched for them on mine to index them.
I wish there was an easier way, but for now there isn’t.
A network of (“thousands of”) servers has — like most things — pros and cons.
Some of the pros are:
- The network is more resiliant against outages. If lemmy.ml is down, all other users can still access the network.
- It’s hard to take legal action against the network or to buy it out (like Big Players™ like to do to get rid of potential competitors).
- It allows various similar or even conflicting moderation policies. The network, i.e. the infrastructure doesn’t allow or prohibit any specific opinion (the communities do).
- It allows for different ways to pay the bills: goodwill of the admin, donaitions, ads, fee or selfhosting. The latter also allows great control over the data so you control your privacy.
Some of the cons are:
- Content is replicated across servers, which increases the total amount of data stored.
- Latency and speed suffer.
- Interoperability with the wider Fediverse is less than 100%, which can create confusion and frustration.
- Discovery is more difficult.
This has definitely been a problem with communities being created on the bigger instances and not utilising smaller instances. Happy for someone to say I’m wrong etc, but I think there would be merit in capping instances to x number of users or communities, to force the user base to spread out.
Also, the way signups work, (ie you find a community you like then click sign up but that signs you up to that instance), further exacerbates the issue and the confusion around how federation works. The sign up links on each instance should lead either to a page with an instance finder, or to a random instance that matches the profile of, and is already federated with, the instance you were on. Otherwise the larger instances have a monopoly and are just going to lead to a bad user experience when they can’t cope with the traffic.
It’s a self defeating prophecy if users only want to sign up to the instances with the big communities, because then everyone is going to keep creating communities there and nobody is going to want to join a smaller instance.
I might be talking nonsense and am happy to be told why that is all wrong :)
Yes, there should be instance caps, and they should be visible to users.
That way users can scale, choose, without much thinking.
This same techinque works everywhere, for example MMO games. You have availability visible and choose servers according to it.
This would fix scaling partially without much technical changes.
If that cap idea was to exist, it would make sense to have it based on the balance of users across the federated servers, so of there’s enough with a similar amount it raises the cap
Since Lemmy instance are not backed by commercial interest, but rather by nice volunteers and donors that have money and time to spare, they will be heavily affected by economic downturns (we still can see commercial interests still affect users negatively tho with reddit). Here are my thoughts on the matter:
- as far as I understand the owner of the domain: https://lemmy.world even has to pay for this fancy domain name in the DNS system … every month subscription service style
- (and tbh I hate the Domain name system) why should I fund it with my own money?
- if you hosted with an onion site over tor that expenditure would not exist, but how would users discover your site then? Let me know if you know something about this
- in times of deflation (meaning money becomes worth more, spending some money on a self hosted lemmy instance becomes nonsensical)
- tbh if I hosted a lemmy instance and the users of my instance posted high quality content in quantity I would use it to train my own LLM, that would at least create some economic incentive for me to host such a page … but managing spam and bots will be HARD
That is why you should always back up your comments on your personal device, would be nice if lemmy had an automated way of doing this (I should look into this more)
Domain names are cheap, like $25/year.
- as far as I understand the owner of the domain: https://lemmy.world even has to pay for this fancy domain name in the DNS system … every month subscription service style
What’s the alternative? You go full-banana decentralised or mega-site Reddit. I think Lemmy is a nice middle ground
Proper data model would be a start, i.e. public-key based identities instead of just the old name@server. That way you could hop from server to server and still be the same account. Would make the whole thing a hell of a lot more robust, as in case of server failure could just continue as if nothing happened on another server.
I’ve suggested a routing protocol to the lemmy devs - to use federated instances to route all the messages to other federated instances. The idea was received with some interest, but it seems that people believe that there’s still a ton of performance that can be squeezed out from the current architecture through optimisations.
I’m quite worried of how well this federation system will work in the long run, especially when more people coming from Rexxit. As people make more post/comments, every federated instance will have to cache more redundant contents from each other, which also will use more storage thus increasing the fee of every instance hoster. There’s also another problem of visibility in search engines. Because Lemmy/Kbin can be hosted by anyone, it makes searching on a specific domain impossible, unlike how I can just add “reddit” in the search query. Also since there are multiple Lemmy/Kbin instances, there’s a chance there’ll be similar communities spread over, fragmenting the communities even further. Until they can find a way to fix those problem, I don’t think federation is suited for large scale communities.
As for fragmentation problem, maybe adding a global search for communities like this will help reducing fragmentation. Users can still make their own community in their instance, while other people who don’t need to can easily find the community they want.
It’s a bit worse than that actually. I’m now seeing several communities with exactly the same name that originate on different servers - so clearly Lemmy doesn’t have a rule about duplication once you cross a server boundary. That’s going to get unwieldy quite fast particularly if, I dunno, “Aww” gets popular on two separate servers at the same time - I guess I’ll have to subscribe to both…
I don’t get argument about duplicates. The same situation was on reddit - you’ve got few, sometimes more, subs about same topic. You could subscribe to whichever you wanted. Why on Lemmy this is suddenly a problem?
I think users are still having trouble with the mental model for browsing Lemmy.
The first interaction with the service is already fragmented - you need to choose where to create an account and start browsing. Even though you can browse communities from other servers, people are now seeing them through the lens of “fragmented” “my server vs other server” and that creates the illusion that these duplicates are somehow a huge issue.
But duplicates can actually be quite useful - a community called “memes” on Lemmy.world could attend to a different audience than a community also called “Memes” but made in an instance entirely in French.
Also, if two instances have two communities you enjoy, with the same name… Subscribe to both? Nothing stops you from doing that. It’s okay. Reddit had “me_irl” and “meirl” which were the exact same, but with different mods, a relatively similar number of subscribers and quite honestly the same content. I didn’t know the actual difference between the two, and I still do not know - I just subscribed to both and kept getting depressing memes to cry before going to sleep. No issues.
Are there ways to manage lists of such? For example, on the former platform that doesn’t deserve a call out, you can do “me_irl+meirl” and aggregate both into one feed. This makes reading the (albeit potentially cross posted) content in a unified feed much easier.
Another similar point I’m having a hard time getting over is that with a centralized platform, it is easy to go to “Subject A”, and see everything on that subject. However, now I need to see “Subject [email protected]”, “Subject [email protected]”, “Subject [email protected]”… Yes, I could subscribe to them all, but this ultimately end up creating a noisy home feed with also “Subject [email protected]”, “Subject [email protected]”, “Subject [email protected]”, “Subject [email protected]”, … etc. all baked into one feed, as opposed to just something focused on “Subject A”.
Lastly, discoverability leaves a lot of room for desire. Today, I’m fairly new to Lemmy, I am actively seeking out communities that I might be interested in, across multiple popular instances, and hoping that federation is enabled between the two instances. Tomorrow, I’d find that I’m subscribed to too many (see the noisy main feed issue above), and I’d remove a bunch. Next week, am I likely to go to the Join Lemmy directory to find new instances, and add “duplicate” communities from newly popular instances? I think not.
I think the long term survival of the platform (to expand beyond just us tech nerds that hate the former platform) will depend a lot on streamlining this workflow to make content discovery much more consistent. Even a simple option where a pseudo “!Community@” (with no instance) feed that aggregates all the “!Community” regardless of instance that you’ve subscribed to, might go a long way.
Discovery really has been the biggest drawback for me. The r/system combined with wikis and sidebars made it very easy to find interesting things.
That’s lacking in lemmy so far. Which, it isn’t a bad thing, barriers to entry have benefits. But from a user perspective, trying to replace reddit, the difficulty in navigating and finding things is frustrating.
But I’m coming from reddit, and they aren’t meant to be the same. The issues are part of what makes it next to impossible for what happened there to happen in a federated system. And I’m so fucking sick of corporate bullshit ruining good things . I figure that lemmy will catch up in feature parity soon enough, and there’s bound to be apps that make it easier to use at some point.
I just wish I had the resources to run a server myself.
Well, by just searching topics in the search bar you can typically find instances related to the search. You need to click the “chain” icon rather than the “federated star” icon to view the post “from your instance” and stay on your personal account.
You need to click the “chain” icon rather than the “federated star” icon to view the post “from your instance” and stay on your personal account.
Woah. I’ve been clicking the star the whole time. This may make things a looot easier.
This is a feature, not a bug. But we definitely need a solution to make subscribing/coalescing them easier for users. Mastodon allows subscribing to topics (hashtags) - I think something similar is needed here, but that will evolve naturally over time.
Maybe have them coalesce based on channel name, but have local mods on each server. It’d be great if you could share moderation between trusted servers or trusted mods on different servers as well (this could be on a per-community or per-server basis).
Yes. This is 100% necessary. Otherwise giant communities would be built and probably all on lemmy.ml
Well one instance shouldn’t monopolize a community. If it takes a dump on one instance at least it exists elsewhere. If I want to start up my own cat community I don’t see why that’s an issue.
I agree, I don’t particularly see this as an actual issue… Nothing stops you from subscribing to both.
Just like there could be a [email protected] and a [email protected]. Nobody is confused with emails when it comes to this… The difference is that it’s slightly more work than reddit because r/aww is one particular thing and it’s assumed we’re talking about Reddit because of it’s unique format. Here it’s just c/aww on lemmy.ml, but that’s a bit of the point of the [email protected] structure of naming.
I LOVE that there’s [email protected] and [email protected]. Different communities ran by different groups will end up with different content. Then I can shop for the content I want myself.
Nobody can singularly own the name. I always found that to be a big problem on reddit. r/trees comes to mind, if there was an actual arborist community that want r/trees, well they were fucked. And that’s kind of jacked. This way it doesn’t matter. Just pick a different instance that doesn’t already have c/trees and post there… or better, start your own instance to host it.
I don’t know… in the future people could even start up instances of lemmy on domains like lemmy.jobs, lemmy.help or lemmy.hobby to aggregate major communities based on topics. lemmy.jobs for instance could be an instance that houses professional the arborist and the domain would make it clear the intent. Or even better… drop the lemmy all together and register jobs.social or similarly descriptive domain names.
I know we’re all a hodge-podge of domains now because a lot of us are just spinning up instance on domains we already have… but the potential is there.
This problem existed on reddit too still. You have r/games r/game r/gamers r/gamenews r/gamernews etc. All trying to do the exact same thing.
I think this comment convinced me. Because you’re right, on Reddit there were always offshoot communities that were essentially the same exact thing just of different sizes and run by different people. There’ll probably always be the “most popular” one, and then several offshoots for the same topic but perhaps a better sense of community because it’s hundreds or thousands of users vs millions or tens of millions of users.
Remembering the exact instance and community name combinations will take a little extra effort, but not significantly and subscribing negates that mostly.
The one that pissed me off a lot is the misspelling of r/politcs trying to mimic r/politics. And i messaged the mods asking why they existed and was just either oblivious or trolled with their answer of “to talk politics”.
Took me forever to realize I was subscribed to an r/mildlyinteresting and an r/mildyinteresting. Just figured they were the same thing and didn’t affect me much.
r/trees comes to mind, if there was an actual arborist community that want r/trees, well they were fucked.
There was. They ended up with, I think, /r/marijuana_enthusiasts or something like that. It was quite funny to both sides, at least it was like 15 years ago.
I’m not sure how this would work, but what about the concept of cross-instance communities? For users it would be a bit like a multi-reddit where you group various communities together into one aggregate list but when posting content you’d have to choose which instance it lands on. Mods would have to agree on a set of rules (and you’d have some communities split off due to differences), but otherwise it seems somewhat plausible.
That would be one way to solve the problem of every instance having a version of one specific type of community.
Yup. I think it’s fun and it makes me explore more. Makes me check out different instances and actually actively look for things I like instead of passive doomscrolling.
That’s true, and the point I guess. You sub to all relevant communities and the overlap isn’t an issue because it’s different communities with different instances making content with others interacting through federation. The “subreddit” is diversified to the top communities in all of the highest subscribed instances. It’s just the nature of the beast, but once you find all the top comms it probably doesn’t seem so bad.
Every server just has a cache … there is no profit for the whole network …
I wouldn’t say that caching is no profit. Yesterday there were several times when lemmy.ml was struggling or effectively down for some people, but despite complaints over there I could read lemmy.ml communities just fine through my instance. Caching meant that I was isolated from the service interruption, and the lemmy.ml server was isolated from my contribution to its load.
As I said, there is no profit from empty instances. Of course, the federation itself is good and fail-proof in this way. But if nobody asks for this cache, it’s just an Internet Archive of a sort.
It only takes one user for an instance to not be empty. Every bit of decentralisation adds resilience to the whole. But more decentralisation adds more resilience, so let’s try to spread out the communities and users.
I just spun up my own instance as well and it does feel a bit like I’m just pulling from the biggest instances and feeding my own without really being able to give much back.
You’re reducing load on the bigger instances by not using them directly, which is giving something back
I have my own Lemmy instance running on my home server, but I’m here. “But Bizzle,” you may be asking yourself, “why go through all the trouble of configuring your own instance just to wind up on Lemmy.World anyway?”
I’m glad you asked! And the answer is that federation only fetches parent comments. I’m glad Lemmy exists, and I’m going to keep using it, but we need federated sibling comments for this to actually be good, in my opinion.
EDIT: I actually couldn’t have been more wrong.
I’m not sure I understand what you’re saying. Did you mean that child comments are not federated?
I don’t think that’s correct.
you mean do something like blockchain ?
