[jiggawatts]

“Do it during the day without an outage.” is my approach.

It requires specific technology choices and planning ahead, but it is especially simple in the web era because they all go through load balancers which are redundant themselves.

The opposite example was Blizzard taking down WoW for half a day every week, which is an absurdly long time.

Even if they had a single server per game world instance, they could have orchestrated updates using automation to take each instance down for a few minutes instead of all of them at once for many hours.

[saalweachter]

My memory was that people generally regarded Blizzard taking down WoW for half a day each week as a mercy, as that was the only time some players had to shower, sleep and eat :-P