What's Actually Tested on AZ-305

What Is on the AZ-305 Exam, and How Should You Prepare?

The AZ-305 Designing Microsoft Azure Infrastructure Solutions exam is not a knowledge quiz. It is a scenario-based assessment that asks you to make architectural decisions under constraint - balancing cost, security, performance, and operational maturity across four core domains. Candidates who pass are not just familiar with Azure services; they can reason through trade-offs and justify a design choice against competing options. If you want to calibrate where your gaps actually are before diving into study, covers data storage decision trees in depth and is worth working through alongside official Microsoft documentation.

Domain 4: Design Business Continuity Solutions

This domain is deceptively specific. It does not test general availability concepts - it tests Azure's concrete mechanisms for backup, disaster recovery, and high availability, and when to use which one.

The decision framework: Every business continuity question begins with two numbers: the Recovery Time Objective (RTO) and the Recovery Point Objective (RPO). RTO is how long you can be down; RPO is how much data you can afford to lose. These two constraints drive the entire architecture. A workload with a 4-hour RTO and 1-hour RPO has completely different design requirements than one with a 15-minute RTO and near-zero RPO.

Azure Site Recovery, Azure Backup, geo-redundant storage with failover, and Always On availability groups for SQL are the primary mechanisms. The exam tests your ability to match RTO/RPO requirements to the right mechanism and configuration - not just to name the service, but to defend why it fits while the alternatives do not.

Worked example: A company runs a Tier-1 ERP application on SQL Server in Azure VMs. The business requires a 30-minute RTO and a 5-minute RPO after a regional failure. Azure Backup alone cannot meet either target - restore times for VMs typically exceed 30 minutes, and backup frequency cannot achieve a 5-minute RPO. The correct design uses Azure Site Recovery for VM replication (enabling near-zero RPO and sub-30-minute failover) combined with SQL Always On availability groups with a replica in the secondary region for the database layer specifically. Azure Backup remains appropriate for long-term retention, but it is not the DR mechanism here.

Availability Zones versus regional redundancy is another recurring decision in this domain. Availability Zones protect against datacenter-level failure within a region; they do not protect against regional outages. Exam scenarios that describe a legal requirement to maintain data within a single geography while surviving a datacenter fire are testing Availability Zone design, not geo-redundancy.

Pulling It Together

The AZ-305 rewards architects who think in constraints rather than catalogs. Memorizing Azure services is insufficient - the exam presents realistic scenarios where three different services could all technically work, and your job is to identify which one fits the specific combination of requirements in front of you.

Practical preparation involves working through scenario-based questions that reflect actual exam depth. The full AZ-305 exam catalog on NerdExam gives you a structured view of coverage alongside practice resources aligned to each domain. Study the decision frameworks above, practice applying them under timed conditions, and pay particular attention to scenarios where two options seem equally valid - those are the questions where understanding the trade-offs separates passing candidates from repeaters.