Google was relatively cozy when I was working there about ten years ago. (But that was as an SRE and in Sydney. I believe the Americans make more of a show of long hours? They always seemed more exhausted in any case.)
I was there through 2016, and I was explicitly told not to work on weekends because it might make others on the team think they would have to do the same.
I really don’t understand that - if you have 20 SREs why would you need to be on call more than 3 weeks a year? If you do get called frequently then you should probably be working shifts anyway.
20 SREs, assuming two different time zones, means ten weeks per year. You need two people in the same continent for the same 12h shift, so that one can drive, take the train home, shower, etc. Within five weeks, you have gone through the entire team.
If your pager response SLO is not that strict and is not impacted by such routines, then you probably can't justify staffing a team of 20, either.
You need 6 people to staff a 24/7 desk on a 6 week rota. That’s not on call, that’s actual work, assuming you don’t need to cover toilet and meal break or handle two fails with equal priority (when I used to work regular nights I’d have a pager when I went to the canteen)
You can do it with 5 but that leaves little room for covering illness and holidays, and you tend to end up paying overtime.
If you are getting frequent call outs out of hours, you need 24/7 coverage at a skill level high enough to reduce the total call outs to just a handful per year.
