Multi-tenant database isolation
Design the database layer for a B2B SaaS serving 50,000 tenants ranging from 5-seat startups to 50,000-seat enterprises, totaling 8 TB and 90k QPS. You must provide strong tenant data isolation, prevent one large tenant from starving others (noisy neighbor), and support per-tenant backup/restore and 'delete all data for tenant X' for compliance. What isolation model and partitioning do you choose?
What a strong answer looks like
Clarify scale and constraints first. Propose a clean component breakdown, then go deep on the hard parts (data model, bottlenecks, consistency, failure modes) and name the trade-offs you are making.
Clarify5:00 left
Estimate5:00 planned
Design15:00 planned
Deep dive12:00 planned
Failure8:00 planned
Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.
Run or narrate your approach, then ask the coach.