I was curious about how many 9s in typical service level agreements translates into how much actual time is allowed by each level of guarantee. A quick Google didn’t yield any quick references, so I turned to Excel and am including it here for future reference. For example, if a service provider offers three 9s, or 99.9% uptime SLA guarantee, how much does that actually allow in terms of time unavailability? Calculated for a regular 365-day year (leap years get you a couple extra seconds), here are the results:
| # of 9s | SLA Guarantee | Minutes of Downtime | Hours of Downtime |
|---|---|---|---|
| 2 | 99% | 5256 | 87.6 |
| 3 | 99.9% | 525.6 | 8.76 |
| 4 | 99.99% | 52.56 | 0.876 |
| 5 | 99.999% | 5.256 | 0.0876 |
| 6 | 99.9999% | 0.5256 | 0.00876 |
| 7 | 99.99999% | 0.05256 | 0.000876 |
So essentially what we’re looking at is that with a 99% guarantee, the provider is allowed a little over 3.5 days of downtime per year, a 99.99% SLA is allowed a little under 1 hour, and seven 9s (99.99999%) guarantees you just 3 seconds of downtime per year. Interesting from a customer perspective, and even more interesting from a provider’s perspective.
I googled my own name and found a link to your site sorry to comment at this section of your site i do not know what sla’s are. When i found your site and began to read about you it was as if i was reading something i had written myself your approach to life and your ideals are very much like mine and i am happy to see people out there have a similar outlook on life i can only hope to be as successful and happy as you appear to be! thank you for doing good with your name. I want also to do good in mine.
Thanks Joshua, glad you like it!
Wow this information is right on. Great Blog! Thanks for making it know to the world.