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<p dir="auto">On 13 May 2021, at 16:19, Niall O'Reilly wrote:</p>
</div><div style="white-space:normal"><blockquote style="border-left:2px solid #777; color:#777; margin:0 0 5px; padding-left:5px"><p dir="auto">I will share my arithmetic separately later.
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<p dir="auto">So, as promised.</p>
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<p dir="auto">Time to recover five-nines availability after worst-case service-recovery delay:</p>
<p dir="auto">An hour’s outage must be matched by a minimum of 99,999 hours uninterrupted<br>
availability.</p>
<p dir="auto">99999 / ( 24 * 365 ) gives 11.4. That’s nearly eleven and a half years.</p>
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<li>
<p dir="auto">Maximum cumulative outage between RIPE meetings which would allow RIPE NCC<br>
to report achieving the five-nines target.</p>
<p dir="auto">RIPE meetings are held twice a year, but not precisely six months apart;<br>
the interval is approximately 180 days.</p>
<p dir="auto">Converting to seconds and dividing by 100,000 is equivalent to multiplying<br>
by 0.864, as there are 86400 seconds in a day.</p>
<p dir="auto">180 * 0.864 gives 155.5 seconds, or just over 2 minutes and 30 seconds.</p>
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<p dir="auto">Best regards,<br>
Niall</p>
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