System designHardsd-g670

Subject Multi tenant databaseLevel Senior–Staff~45 minCommon in Databases & SQL · Distributed systems interviewsIndustries Technology, Software development, IT services

Question

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.

Learn the concepts

Narrate your design

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Run or narrate your approach, then ask the coach.