Asklemmy

Bigger instances will indeed run multiple copies of the various components, it's pretty standard software in that regard.

Usually at first that will start by moving the PostgreSQL database to its own dedicated box, and then start adding additional backend boxes, possibly adding more caching in front so that the backend doesn't have to do as much work. Once the database is pegged, the next step is usually a write primary and one or more read secondaries. When that gets too much, you get into sharding so that you can spread the database load across multiple servers. I don't know much about PostgreSQL but I have to assume it's better than MySQL in that regard and I've seen a 1 TB MySQL database in the wild running just fine.

I think lemmy.world in general is hitting some scalability issues that they're working on. Keep in mind the software is fairly new and is just being truely tested at large scale, there's probably a ton of room for optimization. Also lemmy.world is still on 0.17 and apparently 0.18 changed the protocol a lot in a way that makes it scale much better, so when they complete that upgrade it'll probably run a lot better already.

The part that worries me about scalability in the long term is the push nature of ActivityPub. My server is already getting several POST requests to /inbox per second already, which makes me wonder how that's gonna work if big instances have to push content updates to thousands of lemmy instances where most of the data probably isn't even seen. I was surprised it was a push system and not a pull system, as pull is much easier to scale and cache at the CDN level, and can be fetched on demand for people that only checks lemmy once in a while.

I need to start digging into Lemmy's code and get familiar with the internals, still only a couple days in with my private instance.

Poorly. Lemmy will scale poorly.

I won't be surprised if the larger instances start locking down more as a way to sustain themselves, like restricting communities or only allowing text posts.

Education probably. Back in the day people didn't have any problem understanding that different forums had different capabilities. When MMOs were in full swing, people didn't have problems understanding what being on thr popular server during peak hours meant.

Everyone has just gotten too used to centralization with a lot of money behind it. Eventually people will adjust their expectations. Even if Meta's fediverse attempt takes off, there are always going to be niche communities that exist outside of those spheres, so if people want that, they'll have to move.

The point of the fediverse is having a choice. Some people are going to chose megacorp of the week's offering and that's okay as long a little pockets exist for when people get mad at the megacorp. Also federation leaves space for multiple dominant platforms in a way the current system doesn't.

In short, eventually some instances are going to be bankrolled either through a robust crowdcourcing effort or through being a company. That's okay. The purpose of the fediverse is to allow for smaller niche ideas to be able to breathe without having to adhere to one group's ideals. "If you don't like it, make your own" is a fair statement now

Lemmy is entirely open source, so you can see what their architecture looks like, etc.. here: https://github.com/LemmyNet/lemmy.

Rate limits, as I understand them from the code, should only apply on a per-IP basis. So you should only be seeing rate limit errors if:

• your behind a CGNAT and multiple people who use your ISP are using Lemmy
• you're sending A LOT of requests to your instance yourself
• the admin of your instance has significantly lowered the rate limits (viewable here: /api/v3/site)

My expectation, or at least hope, is that Lemmy will grow horizontally, i.e. more instances for more specialised content, instead of vertically, i.e. more communities in singular, larger instances. Since it's all federated, you can get to stuff in other instances.

I just had an idea. Let's compare reddit and lemmy as land use metaphors.

Reddit is like one monolithic megacity. It's full of communites, some big, encompassing entire neighbourhoods, and others smaller, having one street, one block, maybe even just one building.

Lemmy is like a country, with every instance a city. Some cities are big and varied, others are smaller and specialised, like ones dedicated entirely to fishing or aviation or being German. And you can choose a city to settle in and move between cities for your content. Some cities will be more open to sharing content with residents of other cities, and others will put up bigger restrictions. There are jokes about parts of the userbase on 4chan or Tumblr forming their own subcommunities, and the fediverse allows this in a very material way.

My expectation is that more cities may emerge as people develop more specialised communities. And since there are many cities, there is some resilience in the system. If an instance goes down, you've lost one instance. Out of christ knows how many. Chances are some of its content is duplicated across other instances, so nothing of value is lost. Meanwhile, if (/when) Reddit goes down, all of Reddit is gone.

In short, I hope lemmy develops more, smaller, specialised instances over time. Reddit allowed very niche insterests to have a corner, and despite that, I think the fediverse is more suited to allow for that than a centralised service.

As far as I’m aware lemmy does not support load balancing or high availability as it currently stands. But development is still in its infancy and I’m sure that’s a top priority

Well, I run an instance, too. It's not big at all, but I was thinking about the issue of scaling, too. You can only scale up a single server so much...

But on the other hand, Lemmy is still young. We'll find solutions to that problem.

Also, interesting article. I only took a glance at it, but having only two tables kind of suggests that Reddit is using a relational database. So, if they're not "normalizing" everything, why not use a completely different paradigm, like what MogoDB etc. has?

The way i see it the best way forward would be each community runs there own instance and what we now call communities should become subtopics of that community.

So for example. Asklemmy could be an instance and its members are all people who believe in the value of that instance and want to be involved in sustaining it.

Explainlikeiam5 could be a subcommunities of this instance because its philosophy is largely the same. If asklemmy has plenty of scientist members they could open a askscience subcommunity too.

The majority of user traffic would all come from other smaller homerun instances.

Big instances that try to be everything at once are a side effect of the massive growth we are experiencing, they work now but will slowly become more centralized and are therefore doomed to fail (in my opinion)

To recalculate. How can we help Lemmy grow? By being proactive users that maintain something small we chose to care about.

60,000 users is also a LOT for a Lemmy instance. They've gone from ~8,000 to 60k+ in a matter of weeks. I'm sure there will be many performance and efficiency improvements coming soon. Hopefully people spread out a bit more across other instances with less users!

It’s a challenge, for sure. It is known that there are some inefficiencies in the codebase, which are actively being worked on. But besides that, it’s tricky to know where bottlenecks are until the user influx happens, particularly with the novel federation architecture. Maybe it’s impossible to scale, maybe not, but we only now are seeing a testable use case. I would expect optimization work to start bearing fruit, but these thing take time.

Larger instances will have to monetize to stay afloat. I've gone so far as to buy a domain that is very appropriate for a business-oriented Lemmy instance (specifically for job hunting and career development), but don't yet have time or resources to take it to the next level.

Since Mastodon is using ActivityPub too. How it worked after Elon?

It'll scale horizontally, like E-mail. Lots of different servers operated by various entities. There may be some big players, like Outlook or Gmail, but overall there could be thousands of instances.

Pretty much everything but the database can be infinitely scaled. The database can be somewhat scaled by adding multiple read-only instances. But you're always going to reach a limit where throwing more resources at the write database gives diminishing returns. At that stage you need to shard to increase performance which can be done but it's a similar architecture to having multiple federated instances, so why not just spin up a new instance instead of growing an old one? Another way to lighten the load on instances is with efficient used of relays.

The single instances will probably have issues with scaling, especially the bigger ones. They should find a way to push potential users to sign up on other instances.

Maybe cap instances to a limit based on the number of active users after that you need to join another instance.

The ideal way that ActivityPub federation works IMO is a bunch of smaller nodes coming together to make a large network.

If you have a bunch of people all on one or two instances then you'll have a "central hub" of the network that's constantly overloaded.

That's my advice to community builders on this platform... Spread out across smaller instances, don't just all sign up to a big one.

Lemmy uses PostgreSQL, with a number of tables. It's pretty standard stuff, looks like, and it's in Rust. It's assumed there's only going to be one server per instance right now, but I'd expect that one server could keep up with a reasonable volume.

I already get rate-limited like crazy on lemmy and there are only like 60,000 users on my instance.

Is that a typical number of users to have already? Wow, we really are growing.

Rate limiting is it's own thing, I guess some work will need to be done to find a non-exploitable way to do it that still scales.