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Re:GitHub was down by allanbreyes on Thursday February 27, 2020 @11:37AM (#22434792)
> What is the actual calculation?

Not answering this directly, but the paper Meaningful Availability [0] released recently really changed my opinion on how to calculate and visualize availability. There's a discussion on HN as well [1].

[0]: https://www.usenix.org/system/files/nsdi20spring_hauer_prepu... [1]: https://news.ycombinator.com/item?id=22424173

Re:GitHub was down by thanatropism on Thursday February 27, 2020 @11:57AM (#22435062)
That was insightful to some point. But, of course, the relevant metric is "expected availability" -- before I decide to go on the service; therefore, not the same as "customers served". If I have to think about downtime then my experience is degraded; moreso if I have to delay and batch planned interactions (all of which will later count as successful!)

[Edit: To the point: a high rate of randomly-timed failures is a kind of degraded experience, but not as critical as blocky patches of downtime. A 1% rate of randomly-timed failures is much much much preferred than having the service go out three straight days every February.]

Also: uptime is not the same as "customer delight". It's all about time.

Re:GitHub was down by allanbreyes on Thursday February 27, 2020 @12:24PM (#22435403)
> a high rate of randomly-timed failures is a kind of degraded experience, but not as critical as blocky patches of downtime

Do you think that's an accurate generalization for all software and business contexts? I think a novel insight about the paper is that windowed user uptime is able to visualize the differences. (See Figure 20 from the paper.)

Re:GitHub was down by johannes1234321 on Thursday February 27, 2020 @12:29PM (#22435470)
It certainly is not - a trade might not care about 99% of the time, but the exact moment they want to do a trade the system must work.

Whereas of some GitHub request fails and I retry it's a minor annoyance, but in most cases I won't even know whether that was GitHub's flaw, my local system or some networking in between.