A disaster recovery plan that has never been tested is not a plan - it is a hope. Schedule regular DR drills and fix the gaps you discover.
Strong answers cover: defining RPO (recovery point objective) and RTO (recovery time objective) based on business requirements, backup strategies (incremental, differential, cross-region), automated failover, regular DR testing (not just documentation), and chaos engineering practices. Best candidates have actually tested their DR plans and found gaps.
Critical SRE skill. Many teams have DR plans on paper but never test them. Candidates who have run DR drills and found (and fixed) issues demonstrate operational maturity.