Software bug caused downtime vs infrastructure / hardware availability uptime to me are a different guarantee. I am pretty sure someone did something recently to DynamoDB.

Infrastructure guy here doing this for 14 years. Downtime is downtime. You get a pass if its "scheduled maintenance" you've notified your customers about to allow them to be prepared, but if you silently perform maintenance and it goes to shit, you've just counted against your metrics.

Nope. I still disagree. No service can guarantee 99.999999% unless you discount software upgrade. You just cannot. If you think those nines include software upgrades, you are probably over optimistic.

> No service can guarantee 99.999999%

Don't advertise it if you can't offer it then.

> If you think those nines include software upgrades, you are probably over optimistic.

If you advertise a product with a specific SLA, and you can't meet that SLA, you're a liar. Don't try to blame the victim because of inaccurate/untruthful marketing or engineering.

SLAs are just contractual thresholds for getting some specified redress if not met. They are not promises.

Not meeting a SLA is not lying.

I used SLA to communicate an advertised/marketed level of service. In this case, I agree, that SLA is the wrong term as there is no contractual agreement.

Maybe you are the one who needs to understand their SLA and fine print.