Welcome to your interview.
The question is on your right: Zero-Downtime PII Migration. Take a moment with it first.
Talk your thinking through with me if you like - when you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes). Discussion and graded submissions share your five interviewer interactions, so spend them well.
How would you handle a production database migration involving sensitive personally identifiable information (PII) with zero downtime at Upgrade?