[I used to be a GMail SRE] Correct, it's pretty much impossible for an outage to not be noticed and the GMail on-call being automatically paged. SREs at GMail

[I used to be a GMail SRE] Correct, it's pretty much impossible for an outage to not be noticed and the GMail on-call being automatically paged. SREs at GMail are engineers, yes, but they're very much directly involved with fixing outages - not so much at the 'try turning it off and then turning it on again' level, more the 'redirect all traffic away from this cluster into a different one, while we roll back the broken update'. SRE is a combination of problem-solving when there are outages, and building tools to 1) automate away the manual jobs involved in massive-scale system administration so that outages are less likely to occur.