Comments on: Is 100% uptime really possible? http://www.xaprb.com/blog/2012/07/03/is-100-uptime-really-possible/ Stay curious! Thu, 02 May 2013 12:36:53 +0000 hourly 1 http://wordpress.org/?v=3.5.1 By: Xaprb http://www.xaprb.com/blog/2012/07/03/is-100-uptime-really-possible/#comment-20141 Xaprb Tue, 31 Jul 2012 23:43:09 +0000 http://www.xaprb.com/blog/?p=2760#comment-20141 By the way, some diligent readers of this blog might have noticed several hours of downtime a couple weeks ago while I messed around with DNS. Thank heavens this blog isn’t a critical resource, or I would have learned what I was doing before doing it…

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By: Xaprb http://www.xaprb.com/blog/2012/07/03/is-100-uptime-really-possible/#comment-20140 Xaprb Tue, 31 Jul 2012 23:42:07 +0000 http://www.xaprb.com/blog/?p=2760#comment-20140 mr. stobbe,

Not quite. You mean to say that as time approaches infinity, probability approaches certainty. You are slightly misquoting me: I said that in the time extending from now to infinity, chance becomes certainty. (I should have said it IS certainty, not BECOMES certainty.)

I am treating now-to-infinity as something that exists, not something that unfolds. The time from now to infinity is infinity, not “approaching” infinity. Make sense?

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By: mr.stobbe http://www.xaprb.com/blog/2012/07/03/is-100-uptime-really-possible/#comment-20139 mr.stobbe Tue, 31 Jul 2012 22:24:11 +0000 http://www.xaprb.com/blog/?p=2760#comment-20139 “If there is any chance at all of downtime, then in the time period extending from now to infinity, the chance becomes a certainty.”

Not to be super-nerdy-math-guy here but the probability infinitely approaches certainty, but doesn’t actually reach it. If the probability isn’t 100% to begin with, then it’s impossible to reach 100% regardless of timeline. Mathematically, it is wholly possible to flip a coin an infinite number of times and always come up with heads. Of course, that’s just me being nerdy and your practical point is valid (99.99999…to infinity percent is practically a certainty).

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By: Maciej Wiercinski http://www.xaprb.com/blog/2012/07/03/is-100-uptime-really-possible/#comment-20130 Maciej Wiercinski Tue, 17 Jul 2012 22:56:40 +0000 http://www.xaprb.com/blog/?p=2760#comment-20130 One can safely promise 100% SLA and simply refund for the the time of outage like a lot of companies out there (so yeah, 1% refund for 99% of uptime). Make sure you always read the small print…

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By: hartmut http://www.xaprb.com/blog/2012/07/03/is-100-uptime-really-possible/#comment-20124 hartmut Sat, 07 Jul 2012 10:14:13 +0000 http://www.xaprb.com/blog/?p=2760#comment-20124 The avialability formual was of course supposed to read

Availability = MTBF/(MTBF+MTTR)

and not the other way round.

Thanks to Axel @MPAB for spotting and pointing it out.

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