[hwork]

Just to keep the conversation going: what do you think Twitter's main issues are ? (Or do you think their downtime is not worth mentioning?)

[ericb]

Scalability problems are usually endemic to a particular setup. There is always another bottleneck. The way you're viewing scalability is different than the reality of it.

My previous company (a web testing company) did a load test for a large tax return company. When testing started, their app could support 3 simultaneous users. When the bottlenecks were removed, one by one, the same app (framework, codebase, language and all) supported north of 10,000 users. As you test, there is usually something like a database lock problem, high cpu from a loop that needs to be optimized, bad query/data layout, memory usage maxing out, or something you are running out of, one way or the other.

The people who point out that twitter is not a standard web app and might be better served by messaging have a point also.

[ashu]

What the parent says is that a proper assessment will require an in-depth knowledge of how it is actually implemented. Taking random shots like this article does is like a blind man trying to grope an elephant.

[jamesbritt]

" Taking random shots like this article does is like a blind man trying to grope an elephant."

Groping an elephant seems like a bad idea even for the sighted.

[DanielBMarkham]

I would like to second the call for an immediate stop to elephant groping.

Elephants are a dear and treasured species. This continual assault by blind people and various other gropers have too often left our Loxodonta Africanan friends cowering in terror.

As for RoR, I'll simply quote a good friend of mine. "RoR rocks! Scaling isn't that big a deal. Took us over six months to get the stack just right for a recent customer."

Ugh.