What's Downtime?

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What's Downtime?

Steve Jones - SSC Editor

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April 7, 2018 at 4:07 pm

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t.ovod-everett Default port Points: 1487 More actions · Answer 1

Steve Yegge's (in)famous Google Platforms Rant from 2011 is a fascinating read, but I walked away with a number of important observations from it, one of which was:

monitoring and QA are the same thing. You'd never think so until you try doing a big SOA. But when your service says "oh yes, I'm fine", it may well be the case that the only thing still functioning in the server is the little component that knows how to say "I'm fine, roger roger, over and out" in a cheery droid voice. In order to tell whether the service is actually responding, you have to make individual calls. The problem continues recursively until your monitoring is doing comprehensive semantics checking of your entire range of services and data, at which point it's indistinguishable from automated QA. So they're a continuum.

Eric M Russell SSC Guru Points: 125519 More actions · Answer 2

With a scale-out architecture which allows for individual servers to fail over or be taken offline for maintenance, the questions becomes: At what point of degradation is the application or database "down"? I guess one definition would be when an end user or process needs access to a resource but it isn't available within the terms of an agreed upon SLA. But thanks to technologies like AOG and Azure, that scenario is (or should be) more rare.

"Do not seek to follow in the footsteps of the wise. Instead, seek what they sought." - Matsuo Basho

Robin Wilson SSCarpal Tunnel Points: 4935 More actions · Answer 3

What about if a system or service is very sloooooow, but still returns the correct result in the end? Is that up or down? A customer may have given up, assuming it to be down when, had they waited longer, it would have eventually worked.

Steve Jones - SSC Editor SSC Guru Points: 734418 More actions · Answer 4

robinwilson - Sunday, April 22, 2018 6:17 PM
What about if a system or service is very sloooooow, but still returns the correct result in the end? Is that up or down? A customer may have given up, assuming it to be down when, had they waited longer, it would have eventually worked.

I'd count this as downtime. If the database is unable to complete a query within some multiple of what's expected, it's essentially down.