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Comment by colecut | Hacker News Reader

I think they do this because their priority is decentralization and not speed

No they do this because horizontal scalability is more general. Once you cross the threshold of what your meganode can handle you have to rewrite your code from the bottom up

You can achieve decentralization with a handful of nodes, and you can manage them using simple techniques without inviting the whole large-scale cluster scheduler problem.

What I'm talking about is like 3,000 nodes to serve 15,000 QPS. That seems like a lot of QPS, and so it makes intuitive sense to people that they'd need a big distributed system for it, unless they have a sense of how fast computers actually are.

As this post shows - it really depends on what you're doing :). There are services that can handle 100k QPS on a single machine, no problemo. There are services that can handle as little as 10 QPS per machine. Those are rather extreme cases.

A classic example of a "cheap" service is something like Stack Overflow [1] or Wikipedia: serving content that is mostly static; you just gotta configure your caches well. A classic example of an "expensive" service: a search engine, where so many queries cannot be cached (too rare), or are even completely unique (never seen before [2]).

[1] https://stackexchange.com/performance

[2] https://www.seroundtable.com/google-15-percent-queries-25730...

Right - "those are rather extreme cases." So if you're looking at 5 QPS / node, you should be raising your eyebrows, not automatically reaching for an autoscaling group.

Stack Overflow caches almost nothing. In fact they have just removed most of their remaining caching[1] with no performance hit. Because, surprise, pulling data from a DB and rendering HTML from it is fast, if you're careful about how you do it. The problem with many developers today is that they don't take this level of care.

[1] https://twitter.com/Nick_Craver/status/1280494336673751044?s...

I think people do it because they buy into the hype train of some cloud tech and don't really think about if they need it or not.

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