Availability Formula?

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I am trying to understand what the formula should be for calculating Availability Uptime for different numbers of hours and months.

i.e. for 28, 29, 30 and 31 days.

Each of them for 8 hours or a 24x7x365 calculation.

I was thinking of the formula:

Availability for the month = (No. of Days in that Month) * (Availability Percentage Level).

But how do I incorporate the No. of Hours into this & is it even correct?!



-- Bob Duncan (bobduncan@toughguy.net), March 15, 2004


Take a look at the table in http://www.tarrani.com/availability/availabilitytable.html and the snippet from a service level agreement in http://www.tarrani.com/availability/availabilityexample.html

Mike Tarrani http://www.tarrani.com

-- Mike Tarrani (mike@tarrani.com), March 15, 2004.

Other interesting sources of availability information are at http://www.engr.sjsu.edu/cpham/SJSU/MSEEprojects/RASTutorial.htm http://www.ee.duke.edu/~hairong/BOUND.pdf http://www.sun.com/blueprints/1100/HAFund.pdf http://www.bestpractices.cahwnet.gov/Project%20Samples/CWS-CMS/CWSCMS% 20Service%20Level%20Agreement.pdf http://www.caida.org/outreach/metricswg/faq.xml

-- Mike Tarrani (mike@tarrani.com), March 15, 2004.

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