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HA: What five nines signify in the context of high availability ?

+1 vote

If a system supports less than 5 nines for the high availability then how it is different from the system which supports high availability up to five nines.

posted Feb 28, 2016 by Alok

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2 Answers

+1 vote


5 nines is 99.999%. It means the system must be up for 99.999% of the time.

It could be down for less than 25.92 seconds in a month(30 days) or 315.36 seconds in an year(365 days).
A system is said to be HA only if it meets 5 nines up-time.


answer Feb 29, 2016 by Shivananda Gavalkar S
0 votes

Five nine means 99.999% availability of any system, Which means that you system should not be down for more then .001% in a given period of time. Which translates to max 25 sec outage in a month or 311 seconds outage in a year.

answer Feb 29, 2016 by Salil Agrawal
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