No, you can set up replication with, eg LiteFS where you have one writer and multiple read replicas.
That said, then you have operational overhead that defeats a part of the purpose with SQLite. In practice, you can get very far with a single machine and many CPUs (Postgres is ironically a good example of this). In eg Go you can easily parallelize most workloads. In rails, I don’t know if that’s possible. A quick search suggests there’s a GIL which can be limiting.
This is my perspective as well. You certainly can horizontally scale with SQLite, but I strongly recommend that you vertically until you hit an actual limit there. If you know you will absolutely need multiple app nodes on day 1 or day 10, I think you will probably be better served by choosing a client/server database like MySQL or PG instead.
So, you aren’t limited to single machine, but you should stay single machine as long as possible and extract as much value from that operational simplicity before you trade that simplicity for some kind of horizontal scale
> If you know you will absolutely need multiple app nodes on day 1 or day 10
Yes, but there are a few options even then. First, you can of course tune http caching etc, find traditional bottlenecks.
Second, you can also break the business logic into a separate API endpoint that runs only SQLite + business logic + API responses. Then you can add more frontend nodes in case rendering and other things are most expensive.
The main downside is all logic practically has to be written in the same language as a monolith.
Very true. There isn’t an actual limit. You can horizontally scale with SQLite if you want to or need to. I just think it is worth pushing vertical scaling as far as possible as long as possible. And I don’t actually believe that SQLite is the right tool for every problem or web app. Some apps absolutely should use managed PG/MySQL or serverless PG/MySQL. I think they are the statistical exception and 80% of web apps would be well served with SQLite. But for the other 20%, probably simpler to just start with PlanetScale
