DP-900 Practice Question: Identify considerations for relational data on Azure
A software company develops a multi-tenant SaaS application. They deploy a separate Azure SQL Database for each tenant. The databases are small (2-5 GB) and have highly variable loads — some tenants use the app heavily during the day, others at night. The company wants to maximize resource utilization and minimize costs by allowing databases to share a pool of resources, while still maintaining a predictable performance per database. Which Azure SQL Database deployment option should they choose?
⚠ Common exam trap
Watch out — candidates often confuse elastic pools with single databases, thinking that the vCore model alone provides elasticity, but vCore single databases still allocate dedicated resources per database and lack the shared-pool cost benefit that elastic pools offer for multi-tenant SaaS workloads.
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
✓
Elastic pool
C is correct because an elastic pool allows multiple Azure SQL databases with variable and unpredictable usage patterns to share a fixed pool of resources (eDTUs or vCores), maximizing resource utilization and minimizing cost. The pool provides a predictable performance per database through per-database min/max resource limits, which is ideal for the described multi-tenant SaaS scenario with small databases and highly variable loads.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Single database with DTU purchasing model
Why it's wrong here
Each single database in the DTU purchasing model receives a fixed, isolated allocation of compute and storage based on its selected service tier and performance level. You pay for the maximum provisioned DTUs even when a database is mostly idle, so in a multi-tenant SaaS scenario with many independent databases, costs multiply linearly with tenant count. No resource sharing occurs across databases, so the low average usage pattern that suits an elastic pool is completely unaddressed.
When this WOULD be correct
A single database would be correct if the question specified a single application with a predictable, steady workload that requires dedicated performance isolation, or if the database size exceeds the limits of an elastic pool (e.g., > 4 TB).
- ✗
Single database with vCore purchasing model
Why it's wrong here
The vCore purchasing model for a single database provisions a specific number of virtual cores and memory per database, and while serverless compute can pause or scale down an idle database, it still does not pool resources across multiple databases. Each database is sized and billed independently, meaning a tenancy with hundreds of small databases must independently manage and pay for every database's compute and storage. The aggregation benefit that elastic pools provide—sharing idle capacity among tenants—is absent even with serverless's automatic scaling.
When this WOULD be correct
A company needs a single large database (e.g., >500 GB) with predictable, high-performance requirements and wants to use reserved instances for cost savings, or requires specific vCore-based features like accelerated database recovery or zone redundancy.
- ✓
Elastic pool
Why this is correct
An elastic pool allocates a shared set of DTUs or vCores across a group of Azure SQL databases, automatically distributing capacity based on aggregate demand. For a multi-tenant SaaS app with many low-average, bursty databases, pooling smooths out peaks and reduces cost by paying for a pooled resource budget instead of provisioning each database to its maximum need. Per-database min and max settings let you guard individual tenants from consuming the entire pool, making it the ideal choice for variable usage.
- ✗
Azure SQL Managed Instance
Why it's wrong here
Azure SQL Managed Instance provides a full, isolated SQL Server database engine with instance-scoped features such as SQL Agent, linked servers, common tempDB, and cross-database queries. You pay for the entire instance's compute and storage, regardless of the number of small databases hosted inside, so it is a poor fit for pooling resources among many small tenants. It is justified when the SaaS application explicitly requires instance-level features or stable network integration, but it does not provide the granular per-database cost and scaling of an elastic pool.
When this WOULD be correct
A company wants to migrate an existing on-premises SQL Server application to Azure with minimal changes, requiring near 100% compatibility with SQL Server features like SQL Agent, CLR, and cross-database queries. They have a few large databases (e.g., 100+ GB each) and need predictable performance without resource sharing.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The DP-900 exam frequently reuses these exact scenarios with slightly different constraints.
✓Elastic poolCorrect answer▾
Why this is correct
An elastic pool allocates a shared set of DTUs or vCores across a group of Azure SQL databases, automatically distributing capacity based on aggregate demand. For a multi-tenant SaaS app with many low-average, bursty databases, pooling smooths out peaks and reduces cost by paying for a pooled resource budget instead of provisioning each database to its maximum need. Per-database min and max settings let you guard individual tenants from consuming the entire pool, making it the ideal choice for variable usage.
✗Single database with DTU purchasing modelWrong answer — click to see why▾
Why this is wrong here
Single databases, whether DTU or vCore, do not allow resource sharing across tenants; each database is isolated with its own fixed resources, leading to underutilization and higher costs for small, variable-load databases.
★ When this WOULD be the correct answer
A single database would be correct if the question specified a single application with a predictable, steady workload that requires dedicated performance isolation, or if the database size exceeds the limits of an elastic pool (e.g., > 4 TB).
Why candidates choose this
Candidates may think DTU or vCore models offer flexibility, but they overlook that elastic pools are specifically designed for multi-tenant SaaS scenarios with variable, low-average workloads to maximize resource sharing and minimize cost.
✗Single database with vCore purchasing modelWrong answer — click to see why▾
Why this is wrong here
Single database with vCore purchasing model does not allow databases to share a pool of resources; each database is isolated, leading to underutilization and higher costs for small, variable-load databases.
★ When this WOULD be the correct answer
A company needs a single large database (e.g., >500 GB) with predictable, high-performance requirements and wants to use reserved instances for cost savings, or requires specific vCore-based features like accelerated database recovery or zone redundancy.
Why candidates choose this
Candidates may think vCore offers more flexibility and cost control, but they overlook that elastic pools are specifically designed for sharing resources among multiple databases with variable loads.
✗Azure SQL Managed InstanceWrong answer — click to see why▾
Why this is wrong here
Azure SQL Managed Instance is designed for lift-and-shift migrations of large numbers of databases with full SQL Server compatibility, not for sharing resources among many small databases with variable loads. It does not provide the elastic pooling capability needed to maximize utilization and minimize costs for multi-tenant SaaS.
★ When this WOULD be the correct answer
A company wants to migrate an existing on-premises SQL Server application to Azure with minimal changes, requiring near 100% compatibility with SQL Server features like SQL Agent, CLR, and cross-database queries. They have a few large databases (e.g., 100+ GB each) and need predictable performance without resource sharing.
Why candidates choose this
Candidates may think Managed Instance offers better performance or isolation for multi-tenant workloads, or they confuse it with elastic pools because both are managed services. The name 'Managed Instance' sounds like a flexible option for multiple databases.
Analysis generated from the official DP-900blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DP-900 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-900 exam.