AZ-305 - Design Business Continuity Solutions (13% of the exam) - Section 3.2

Design for high availability using availability zones, availability sets, and multi-region architectures.

Distinguish availability zones, availability sets, and zone-redundant services and select the right pattern to meet a target SLA for virtual machines, databases, and platform services. Design active-active and active-passive multi-region topologies and compose individual service SLAs to predict end-to-end availability.

availability zonesavailability setszone-redundant servicesactive-active and active-passiveSLA composition

Practice question for this objective

Free sampleDesign Business Continuity Solutionsmedium

Your AZ-305 design must support a mission-critical workload with an RPO of 0 across zones and an RTO under 60 seconds across regions. The Availability Zones documentation recommends that mission-critical workloads use both multi-region and multi-zone solutions together. Is this statement correct?

AYes Correct
BNo

Mission-critical = multi-region AND multi-zone in the documented Availability Zones guidance. Azure Availability Zones guidance states that production workloads should use multiple availability zones if the region supports them, and that for mission-critical workloads architects should consider a solution that is both multi-region and multi-zone.

Why A is correct: Correct. Azure Availability Zones guidance states that production workloads should use multiple availability zones if the region supports them, and that for mission-critical workloads architects should consider a solution that is both multi-region and multi-zone.

Why B is wrong: Choosing multi-zone without multi-region leaves the workload exposed to a full-region outage; choosing multi-region without multi-zone keeps the in-region SLA capped below 99.99% for VM tiers. The documented mission-critical pattern combines both.

See more AZ-305 practice questions, answers explained.

Exam traps in Design Business Continuity Solutions

Answers that look right on this material and are not. Each one is a distractor from a different question in the AZ-305 bank for this domain.

Default fault domains are 3 (maximum 5); default update domains are 10 (maximum 20).
Why it is wrong: Default fault domains are 2 with a maximum of 3, not 3 with a maximum of 5; update domain defaults are 5, not 10.
Two or more VMs in the same single zone reach 99.99%; inter-zone latency target is under 10 ms.
Why it is wrong: 99.99% requires VMs in different zones, not the same zone, and inter-zone latency targets less than 2 ms, not 10 ms.
Availability zones protect against a full-region outage in addition to in-region failures.
Why it is wrong: Documentation explicitly states zones do not protect against full-region outages; multi-region designs are required for that.

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