It is a bit surprising actually. It means they haven't built their app to be tolerant of single DC loss, either on purpose or because they didn't test it proper

It is a bit surprising actually. It means they haven't built their app to be tolerant of single DC loss, either on purpose or because they didn't test it properly. Purely conjecture, but I suspect since github uses mysql cluster they only write to a single dc, which would be the primary dc that failed in this case.