Yeah, it's possible. Just not pleasant. What they're doing (and how unpleasant it is to operate) will depend on exactly what they mean by: > Your instance mi

Yeah, it's possible. Just not pleasant. What they're doing (and how unpleasant it is to operate) will depend on exactly what they mean by: > Your instance might experience a short period of decreased performance and how tolerant they are of unplanned reboots. I suspect what it means is that they'll throttle your VM (or maybe pause your IO) so it can't interfere with finalising the migration. That being said, this is Google. They've probably thrown more man-hours at this than anyone else would think sane. I'll note that this is in the context of automatic migration away from "maintenance events" (whatever that covers) - it sounds like they think they've automated away a lot of the reasons we were having to keep an eye on things, but they're still vulnerable to hardware failure (obviously).