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Scalable, by definition, means more nodes = more capacity. Speed has nothing to do with it. A simple stateless website that requires no shared data like from
by zepolen 18y ago
Scalable, by definition, means more nodes = more capacity.
Speed has nothing to do with it.
A simple stateless website that requires no shared data like from a db, is scalable, since you can add more web servers to fulfill more requests.
Using memcached, however, isn't scaling, because while memcached itself does scale, if the backend it reads from doesn't, the whole system doesn't.
- FooBarWidget 18y agoEven so, there's a limit to how many nodes you can add given an architecture. Scale from 1 concurrent user to 1000? No problem, just add a server. Scale to 100000? Add many servers, and load balancers, maybe master-slave replication for database. Scale to 10 million? Putting more boxes in your data center help you anymore because your data center is full, you don't have enough bandwidth and even the master-slave database setup you had overloaded. You need to setup multiple geographically distinct data centers in the world and shard your database. What if you have 100 billion users? Adding more data centers on the same planet won't help anymore; I don't even know whether anybody is technically capable of serving 100 billion concurrent users. Sure, the latter architecture can serve 1 concurrent user, but it's also 100000 times more expensive. The answer is not as simple as "it scales or it does not".
- zepolen 18y agoFair enough, I just wish articles would stop using the word 'scalable' to describe everything.