Salami

Asking the important questions

They just upgraded to a dedicated server for 180€/month today.

Fwiw, he has been providing quite a lot of transparency in his posts to this community. He's shared his hardware config in detail, posted maintenance posts with brief descriptions of what he's doing, and replied to comments around specific config tweaks. I haven't catalogued a list of links, but I've seen him do all of these things in the last 48h. It's easy to imagine that all these things could be compiled in real time into a how-to, but it's a pretty big deal just to keep the lights on right now, and pretty difficult to understand whether tweaks that helped your setup are generally applicable or only situationally useful and happen to perform well for your specific setup.

I'm sure we will see more high-performance Lemmy guides in the future, but at this point no one has more than 36h of experience with high-performance Lemmy. Give them a minute to catch up.

More like throw more $$$ at the problem has been the solution.

I definitely second the motion on it being a branding problem. Stuff like sh.itjust.works seem to me like something that dark basement tech nerds would come up with that is "edgy" and really only used by them and other people like them.

I'm not really into the ironic "edgy" aesthetic and part of the struggle with this transition for me has been orienting myself in the space because I don't want to commit to some "sketchy" edgelord URL

I do think join-lemmy.org could possibly be changed to show server usage/capacity and uptime. When I initially signed up I went for lemmy.ml because what the heck is the difference? Honestly I was having all kinds of timeouts and thought the entire lemmy-verse was probably struggling. I was concerned that was the experience everyone was getting that they were going to leave because it is unsustainable.

But I ended up seeing a page showing the uptime of serversnand lemmy.world was 100% (at that point). So I figured I'd start an account here. HOLLY CRAP IT IS SO MUCH FASTER. I would have had a hard time sticking around if it all worked like lemmy.ml.

I started a community on lemmy.ml. Wish I would have done it here.

Yeah, I get it. Naming optics aside, it seems an instance with a lot of headroom relative to others, with a capable team. Would be near the top of my word-of-mouth options in spite of the idiosyncratic name.

It's important to recall that last week the biggest lemmy server in the world ran on a 4-core VM. Anybody that says you can scale from this to reddit overnight with "horizontal scaling" is selling some snake oil. Scaling is hard work and there aren't really any shortcuts. Lemmy is doing pretty well on the curve of how systems tend to handle major waves of adoption.

But that's not your question, you asked if Lemmy can horizontally scale. The answer is yes, but in a limited/finite way. The production docker-compose file that many lemmy installs are based on has 5 components. From the inside out, they are:

• Postgres: The database, stores most of the data for the other components. Exposes a protocol to accept and return SQL queries and responses.
• Lemmy: The application server, exposes websockets and http protocols for lemmy clients... also talks to the db.
• Lemmy-ui: Talks to Lemmy over websockets (for now, they're working to deprecate that soon) and does some fancy dynamic webpage construction.
• Nginx: Acts as a web proxy. Does https encryption, compression over the wire, could potentially do some static asset caching of images but I didn't see that configured in my skim of the config.
• Pict-rs: Some kind of image-hosting server.

So... first off... there's 5 layers there that talk to each other over the docker network. So you can definitely use 5 computers to run a lemmy instance. That's a non-zero amount of horizontal scaling. Of those layers, I'm told that lemmy and lemmy-ui are stateles and you can run an arbitrary number of them today. There are ways of scaling nginx using round-robin DNS and other load-balancing mechanisms. So 3 out of the 5 layers scale horizontally.

Pict-rs does not. It can be backed by object storage like S3, and there are lots of object storage systems that scale horizontally. But pict-rs itself seems to still need to be a single instance. But still, that's just one part of lemmy and you can throw it on a giant multicore box backed by scalable object storage. Should take you pretty far.

Which leaves postgres. Right now I believe everyone is running a single postgres instance and scaling it bigger, which is common. But postgres has ways to scale across boxes as well. It supports "read-replicas", where the "main" postgres copies data to the replicas and they serve reads so the leader can focus on handling just the writes. Lemmy doesn't support this kind of advanced request routing today, but Postgres is ready when it can. In the far future, there's also sharding writes across multiple leaders, which is complex and has its downsides but can scale writes quite a lot.

All of which is to say... lemmy isn't built on purely distributed primitives that can each scale horizontally to arbitrary numbers of machines. But there is quite a lot of opportunity to scale out in the current architecture. Why don't people do it more? Because buying a bigger box is 10x-100x easier until it stops being possible, and we haven't hit that point yet.