Windows . . .
And yes! It took a few minutes, but if I kept hitting refresh eventually the "shutdown" message went away!!! It was the first time I had seen this, but then typically I don't hit refresh . . .
So . . . I get where you are coming from wanting a stable system to backup . . . but this seems like a pretty heavy handed way to get it. It is a pretty shocking thing for a user to see who isn't in the know . . . and if they have the ability, they are likely to cancel on you anyway.
Plus on my "almost nothing" Jenkins the backup took 1 minute or so . . . on our big production Jenkins with all the data and history, it will be interesting to see how long it lasts . . . it could be awhile.
Clearly this is upsetting (to users) enough that it will have to be done at night, but we are a world wide 7/24 operation. I have a smaller community to upset in Hyderabad than I do in San Diego, but it is hard to select a backup time that won't alarm one of them. Plus night time is the time for "big builds" . . . the multi-hour things nobody want to do during the day . . . I am reluctant to take a big chunk of time out of that already busy schedule . . . no easy solutions here.
It might be interesting to see if KK would add a new "mode" . . . shutdown like in that tables/files don't change, but instead of a big red banner saying shutdown, a (say) blue banner saying "backup in progress" . . . something to clue the user into the "real situation".
Thanks for looking into this . . . sorry the solution is "I just didn't understand" . . .