So. I don't understand the 5 nines they promote. One bad day those nines are gone. So they next year you are pushing 2 nines.

Its just fabricated bullshit. It's how all the companies do it. 99.999% over a year is literally 5 minutes. Or under an hour in a decade, that's wildly unrealistic.

Reddit was once down for a full day and that month they reported 99.5% uptime instead of 99.99% as they normally claimed for most months.

There is this amazing combination of nonsense going on to achieve these kinds of numbers:

1. Straight up fraudulent information on status page. Reporting incendents as more minor than any internal monitors would claim.

2. If it's working for at least a few percent of customers it's not down. Degraded is not counted.

3. If any part of anything is working then it's not down. For example with the reddit example even if the site was dead as long as the image server is still at 1% functional with some internal ping the status is good.