High availability of services, when the downtime is less than 5.26 minutes per year (This article has a table that shows the conversion from "nines" to the amount of time a system would be unavailable for various periods.)
Super League World Nines | Veneto's Nines | rugby league nines | Rollin' with the Nines | Ninety-Nines |
Wilfred Owen mentions being shelled by "Five-Nines" in his poem Dulce et Decorum est.