Comments on: In Search of Five 9s - Calculating Availability of Complex Systems http://www.edgeblog.net/2007/in-search-of-five-9s/ Notes from the edge Tue, 06 Jan 2009 13:21:30 +0000 http://wordpress.org/?v=abc hourly 1 By: Hisham Ghanem http://www.edgeblog.net/2007/in-search-of-five-9s/comment-page-1/#comment-67268 Hisham Ghanem Sun, 15 Jun 2008 14:13:02 +0000 http://www.edgeblog.net/2007/in-search-of-five-9s/#comment-67268 Hi, Great article and formulas posed through the site: http://www.availabilitydigest.com./public_articles/ article "Calculating Availability - Redundant Systems". I notived though that the "Multiple Nodes, Multiple Spares" formula has an issue with the (-1)!, when #of nodes = # of spares. Did I miss a point when reading the article? Thanks. Hi,
Great article and formulas posed through the site:
http://www.availabilitydigest.com./public_articles/
article “Calculating Availability - Redundant Systems”.
I notived though that the “Multiple Nodes, Multiple Spares” formula has an issue with the (-1)!, when #of nodes = # of spares.

Did I miss a point when reading the article?

Thanks.

]]> By: Chris Loosley http://www.edgeblog.net/2007/in-search-of-five-9s/comment-page-1/#comment-27583 Chris Loosley Thu, 01 Nov 2007 00:42:57 +0000 http://www.edgeblog.net/2007/in-search-of-five-9s/#comment-27583 <p>Bill,<br /> Nice analysis! </p> <p>I responded to your comment on my blog http://www.webperformancematters.com/performance-forum/post/296647 listing some of my own posts on this topic. My analysis was at a much higher level than yours, more like an introduction to the concepts you are working with in your formulas.</p> <p>--Chris</p> Bill,
Nice analysis!

I responded to your comment on my blog http://www.webperformancematters.com/performance-forum/post/296647 listing some of my own posts on this topic. My analysis was at a much higher level than yours, more like an introduction to the concepts you are working with in your formulas.

–Chris

]]> By: bill http://www.edgeblog.net/2007/in-search-of-five-9s/comment-page-1/#comment-27568 bill Wed, 31 Oct 2007 22:33:16 +0000 http://www.edgeblog.net/2007/in-search-of-five-9s/#comment-27568 Mr. Highleyman, Great tip! For anyone who liked my article, but wants to see the math expressed more eloquently, go immediately to this site and read: http://www.availabilitydigest.com./public_articles/0101/calculating_availability.pdf The basic calculations are the same, but his equations are much better than mine. -Bill Mr. Highleyman,

Great tip! For anyone who liked my article, but wants to see the math expressed more eloquently, go immediately to this site and read: http://www.availabilitydigest.com./public_articles/0101/calculating_availability.pdf

The basic calculations are the same, but his equations are much better than mine.

-Bill

]]> By: Bill Highleyman http://www.edgeblog.net/2007/in-search-of-five-9s/comment-page-1/#comment-27553 Bill Highleyman Wed, 31 Oct 2007 20:24:45 +0000 http://www.edgeblog.net/2007/in-search-of-five-9s/#comment-27553 I really enjoyed your article on five 9s. High availability is a field that I specialize in. You might want to check out the Availability Digest, a free monthly digest of high availability issues, at www.availabilitydigest.com. Go to the Article Archives and look under The Geek Corner. There you will find a series of papers on calculating availabity using effectively the same equations you use, though in a different form. - Bill Highleyman I really enjoyed your article on five 9s. High availability is a field that I specialize in. You might want to check out the Availability Digest, a free monthly digest of high availability issues, at http://www.availabilitydigest.com. Go to the Article Archives and look under The Geek Corner. There you will find a series of papers on calculating availabity using effectively the same equations you use, though in a different form.

- Bill Highleyman

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