Multi Tenancy and Data Consistency Questions

Designing multi tenant systems that ensure strong operational and security boundaries between tenants while maintaining correct and performant data across geographic regions. Candidates should be able to discuss tenant isolation patterns including separate schemas, separate databases, separate storage buckets, logical partitioning, and virtual data warehouses; access control and encryption strategies to prevent cross tenant data leakage; deployment and network isolation options. They should also cover multi region replication and synchronization approaches, trade offs between strong consistency and eventual consistency, conflict detection and resolution strategies, per tenant and per region data residency and compliance considerations, backup and recovery with geographic redundancy, testing and verification of isolation and consistency properties, monitoring and alerting for replication lag or leakage, and operational concerns such as migration, scaling, and performance isolation.