Availability
How long is a system working? This means functional and responding.
It’s common to measure it as a percentage:
System Availability
| % of Uptime | Daily Downtime | Weekly downtime | Monthly downtime | Yearly downtime |
|---|---|---|---|---|
| 99 | 14m:24s | 1h:40m:48 | 7h:8m:17s | 3d:15h:39m |
| 99.9 aka 3 Nines | 1m26s | 10m4.8s | 43m49.7 | 8h45m57 |
| 99.95 | 43s | 5m2.4s | 21m54s | 4h22m58s |
| 99.99 aka 4 Nines | 8.6s | 1m0.5s | 4m23s | 52m35.7s |
| 99.999 aka 5 Nines aka Very Expensive | 0.9s | 6.0s | 26.3s | 5m 15.6s |