DP-300 Plan and implement data platform resources Practice Question
You are deploying Azure SQL Database for a multi-tenant SaaS application. Each tenant has its own database. You need to ensure that tenant data is isolated and that performance is predictable. Cost efficiency is important. Which deployment model should you use?
⚠ Common exam trap
Watch out — candidates often confuse 'tenant isolation' with 'dedicated resources' and choose Option A, missing that elastic pools provide logical isolation (separate databases) with shared, cost-efficient resources, which is the exact requirement for predictable performance and cost efficiency in multi-tenant SaaS.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use an elastic pool with one database per tenant
An elastic pool allows you to provision a shared set of resources (eDTUs or vCores) that is distributed across multiple databases, each representing a tenant. This provides logical isolation of tenant data (each tenant has its own database) while pooling resources to handle variable workloads cost-effectively. The elastic pool model is specifically designed for SaaS multi-tenant scenarios where predictable performance is achieved through resource governance, and cost efficiency comes from sharing resources among databases that do not all peak simultaneously.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Deploy a single Azure SQL Database per tenant
Why it's wrong here
A database per tenant gives isolation but multiplies minimum compute cost across tenants, undermining the cost-efficiency requirement. It is tempting because per-tenant databases provide strong data isolation and predictable performance, and would be correct when tenant count is small and budgets are generous.
- ✗
Use Azure SQL Managed Instance with multiple databases
Why it's wrong here
Azure SQL Managed Instance runs a dedicated instance billed continuously, so multi-tenant cost efficiency suffers compared with elastic pools. It is tempting because Managed Instance supports near-full SQL Server compatibility and instance-scoped isolation, and would be correct for lift-and-shift workloads needing those features.
- ✗
Use a single large database with row-level security
Why it's wrong here
Row-level security filters rows within one database, so all tenants share its compute and storage; noisy-neighbour contention prevents predictable per-tenant performance. It is tempting because RLS genuinely isolates rows cheaply when tenants are few and workloads uniform, but the stem requires separate databases with independent, predictable resources.
- ✓
Use an elastic pool with one database per tenant
Why this is correct
An elastic pool shares provisioned eDTUs or vCores across many single-tenant databases, so each tenant keeps its own database for isolation while aggregate resources absorb unpredictable per-tenant load spikes. This satisfies the predictable-performance and cost-efficiency constraints, since you pay for pooled capacity rather than peak provisioning per database.
Go deeper
Related to this question
Learn chapter
Implementing High Availability for Azure SQL Databases
Key term
Azure SQL Performance Tuning
Azure SQL Performance Tuning is the process of optimizing the speed and efficiency of queries and database operations in Microsoft Azure SQL Database or SQL Managed Instance to reduce latency and improve throughput.
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Written by Johnson Ajibi, MSc IT Security
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This DP-300 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DP-300 exam.