How much downtime an availability target actually allows. Months are 30 days and years are 365, which is close enough for arguing about SLAs.
Cheat sheet
| Target | Per month | Per year |
|---|---|---|
| 99% | 7h 12m | 3d 15h 36m |
| 99.9% | 43m 12s | 8h 45m 36s |
| 99.95% | 21m 36s | 4h 22m 48s |
| 99.99% | 4m 19s | 52m 34s |
| 99.999% | 26s | 5m 15s |