AZ-305 Design data storage solutions Practice Question
A SaaS company uses Azure SQL Database for a multi-tenant application. They have 80 tenant databases, each with varying and unpredictable usage patterns. The company wants to optimize costs without sacrificing performance and wants the ability to easily add new tenant databases without over-provisioning. Which deployment option should they use?
⚠ Common exam trap
Candidates often choose Single Azure SQL Database per tenant (Option B) because they think it provides isolation and simplicity, but they overlook the cost inefficiency of over-provisioning for unpredictable peaks, which is exactly the problem elastic pools solve.
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
✓
Azure SQL Database elastic pool
Azure SQL Database elastic pool is the correct choice because it allows multiple tenant databases to share a fixed set of resources (DTUs or vCores), automatically absorbing the unpredictable usage spikes of individual tenants without over-provisioning. This model optimizes cost by paying for the pooled resources rather than each database's peak capacity, and new tenant databases can be added seamlessly to the pool without upfront resource allocation.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Azure SQL Database elastic pool
Why this is correct
For a multi-tenant SaaS workload, elastic pools let you purchase a shared set of eDTUs or vCores that is distributed across many Azure SQL databases. This model excels when tenant usage is intermittent and peaks do not align, so the aggregate resource consumption is far lower than the sum of individual peak requirements, reducing overall cost while maintaining predictable per-database pricing.
- ✗
Single Azure SQL Database per tenant
Why it's wrong here
With a single Azure SQL Database per tenant, each tenant's database must be provisioned at its own DTU/vCore tier to handle that tenant's peak demand. Because most tenants rarely sit at peak, you pay for idle reserved capacity across the fleet, leading to substantial waste as tenant count grows and making cost management linear and inefficient compared to pooling.
- ✗
Azure SQL Managed Instance
Why it's wrong here
Azure SQL Managed Instance provides near-total SQL Server compatibility and instance-scoped features such as SQL Agent, linked servers, and CLR, making it a great choice for lift-and-shift migrations, but not for hosting hundreds of small tenant databases. Each instance has a minimum compute and storage footprint, and you cannot share resources across tenant databases as you would in an elastic pool, so costs remain high for a many-small-database SaaS.
- ✗
Azure SQL Database Hyperscale
Why it's wrong here
Hyperscale is an architecture designed for single databases that need to grow beyond 4 TB, require rapid scale-out, or expect extremely high transaction log throughput. For a typical multi-tenant SaaS with many small databases, Hyperscale's per-database storage and compute costs are far higher than pooled provisioning, and it does not provide any mechanism to share resources across tenants, making it economically unsuitable for this scenario.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This AZ-305 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 AZ-305 exam.