AZ-305 · Domain 3 of 4

AZ-305 Domain 3: Design business continuity solutions

This domain covers keeping solutions available and recoverable: designing backup and disaster recovery for compute, databases and data to meet RTO and RPO, and designing high availability across compute and data tiers.

Exam format
15–20%
Official functional groups
2
Assessment estimate
7–10
Suggested study time estimate
15–20 hrs

About 9 min read Reviewed October 2026

Overview

Design business continuity solutions covers designing for recovery and availability. It has two objective groups. Designing backup and disaster recovery covers recommending a recovery solution for Azure and hybrid workloads that meets recovery objectives, and backup and recovery for compute, databases and unstructured data, using Azure Backup and Azure Site Recovery. Designing for high availability covers recommending high availability for compute, relational data, and semi-structured and unstructured data, using availability zones, replicas and redundancy.

At 15–20%, this is the smallest AZ-305 domain, but business continuity is essential architecture. The exam rewards matching the recovery and availability design to the stated recovery time objective (RTO) and recovery point objective (RPO) and availability targets, and distinguishing backup (data protection and restore) from disaster recovery (failover) from high availability (staying up through local failures).

How it's tested

AZ-305 questions in this domain state RTO, RPO and availability requirements and ask you to recommend the continuity design. AZ-305 questions are requirement-driven design scenarios where several options may work, so read every requirement and recommend the design that meets all of them before answering.

  • Meet RTO and RPO

    Recovery objectives are stated, and you recommend the backup or disaster-recovery design that meets them.

  • Backup or failover

    A recovery need is described, and you recommend Azure Backup for data or Site Recovery for regional failover.

  • Design high availability

    An availability target is stated, and you recommend availability zones, replicas or redundancy.

Reasoning it through

A workload must resume in another Azure region within minutes of a regional outage, with minimal data loss. Azure Backup restores data but is too slow for a minutes-level recovery of running workloads. Azure Site Recovery continuously replicates the workload to a secondary region and orchestrates failover, meeting a low RTO and RPO, which is the disaster-recovery design the exam expects for regional failover.

Functional groups 2

Official functional groups from the Microsoft outline, in outline order.

3.1 Design solutions for backup and disaster recoveryRecovery for Azure and hybrid workloads, and backup for compute, databases and data, to meet RTO and RPO.
What it means
This covers recommending a recovery solution for Azure and hybrid workloads that meets recovery objectives, and backup and recovery solutions for compute, databases and unstructured data, using Azure Backup, Recovery Services vaults, Azure Site Recovery and database and storage protection features.
What to understand
Azure Backup protects and restores data on a policy schedule; Azure Site Recovery replicates workloads to a secondary region and orchestrates failover. The recovery objectives, RTO (how fast to recover) and RPO (how much data loss is acceptable), drive the design and its cost. Hybrid workloads can be protected too.
How it shows up
A recovery requirement with RTO and RPO is described, and you must recommend the backup or disaster-recovery design.
Common confusion
Confusing Azure Backup with Azure Site Recovery; Backup restores data, while Site Recovery replicates and fails over workloads.
3.2 Design for high availabilityHigh availability for compute, relational data, and semi-structured and unstructured data.
What it means
This covers recommending high availability solutions for compute using availability zones, availability sets and scale sets, for relational data using zone-redundant configurations and replicas, and for semi-structured and unstructured data using zone-redundant and geo-redundant storage.
What to understand
High availability keeps a solution running through local failures, such as spreading compute across availability zones and using zone-redundant databases and storage. It differs from disaster recovery, which handles regional outages. The design matches the availability target without unnecessary cost.
How it shows up
An availability target is described, and you must recommend the high-availability design for compute or data.
Common confusion
Confusing high availability with disaster recovery; high availability handles local failures, while disaster recovery handles regional outages.

High-yield concepts

The terms, rules and formulas this domain turns into questions most often.

  • RTO vs. RPO

    Recovery time objective versus recovery point objective.

    Remember
    RTO is how fast; RPO is how much data loss.
    Tested as
    Recovery design questions.
    Trap
    Confusing the two.

  • Azure Backup

    Policy-based backup and restore of data.

    Remember
    For data protection and accidental loss.
    Tested as
    Backup questions.
    Trap
    Using it for regional failover.

  • Azure Site Recovery

    Replicates workloads and orchestrates failover.

    Remember
    For regional disaster recovery.
    Tested as
    DR questions.
    Trap
    Using it for routine data restore.

  • High availability vs. disaster recovery

    Local-failure resilience versus regional recovery.

    Remember
    HA stays up; DR recovers.
    Tested as
    Continuity questions.
    Trap
    Treating them as the same.

  • Availability zones

    Physically separate datacenters in a region.

    Remember
    They protect against datacenter failure.
    Tested as
    HA design questions.
    Trap
    Confusing with availability sets.

  • Zone-redundant services

    Services replicated across zones.

    Remember
    Zone-fault tolerant databases and storage.
    Tested as
    HA design questions.
    Trap
    Expecting regional protection from zones.

  • Geo-redundant storage

    Storage replicated to a secondary region.

    Remember
    Survives a regional outage.
    Tested as
    Durability questions.
    Trap
    Confusing with zone redundancy.

  • Recovery Services vault

    Stores backups and Site Recovery data.

    Remember
    The container for backup and DR.
    Tested as
    Backup questions.
    Trap
    Confusing vault scopes.

  • Database HA and replicas

    Zone-redundant configurations and read replicas.

    Remember
    They keep databases available.
    Tested as
    Data HA questions.
    Trap
    Confusing read replicas with failover.

  • DR strategy by objective

    Backup and restore to active-active by RTO and RPO.

    Remember
    Lower objectives cost more.
    Tested as
    DR questions.
    Trap
    Over-provisioning for loose objectives.

Side by side

Concepts candidates mix up, compared on the point that decides the answer.

High availability vs. disaster recovery vs. backup

ConceptMeaningKey differenceCommon trap
High availability Stays up through local failure Zones and redundancy Confusing with DR
Disaster recovery Recovers from a regional outage Site Recovery failover Confusing with backup
Backup Restores data Azure Backup Using it for failover

Azure Backup vs. Azure Site Recovery

ConceptMeaningKey differenceCommon trap
Azure Backup Backs up and restores data Data loss and deletion Using it for regional failover
Azure Site Recovery Replicates and fails over Regional disaster recovery Using it for routine restore

Availability zones vs. geo-redundancy

ConceptMeaningKey differenceCommon trap
Availability zones Separate datacenters in a region Datacenter-failure protection Expecting regional protection
Geo-redundancy Replicated to another region Regional-outage protection Confusing with zones

Exam traps

Each trap is an answer that looks right. Learn the clue that should change your mind.

  1. Backup for regional failover

    What candidates pick
    Recommend Azure Backup to fail a workload over to another region within minutes.
    Why it looks right
    Backup protects data.
    Why it's wrong
    Azure Site Recovery replicates and fails over workloads for a low RTO; Backup restore is too slow.

    Clue to watch for The requirement is minutes-level regional failover.

  2. Zones for regional outage

    What candidates pick
    Recommend availability zones to survive a whole-region failure.
    Why it looks right
    Zones add resilience.
    Why it's wrong
    Zones are within one region; a regional outage needs geo-redundancy or Site Recovery to another region.

    Clue to watch for The requirement is to survive a regional outage.

  3. HA equals DR

    What candidates pick
    Recommend a zone-redundant design and call it disaster recovery.
    Why it looks right
    Both improve resilience.
    Why it's wrong
    High availability handles local failures; disaster recovery handles regional outages and needs cross-region design.

    Clue to watch for The requirement is recovery from a regional disaster.

  4. Over-provisioned DR

    What candidates pick
    Recommend active-active multi-region for a generous RTO.
    Why it looks right
    It recovers fastest.
    Why it's wrong
    A loose RTO can be met more cheaply with backup and restore or warm standby.

    Clue to watch for The RTO and RPO are generous and cost matters.

  5. Read replica for failover

    What candidates pick
    Recommend a read replica as the database high-availability solution.
    Why it looks right
    A replica is another copy.
    Why it's wrong
    Read replicas scale reads; zone-redundant or failover configurations provide availability.

    Clue to watch for The need is database failover, not read scaling.

Answer framework

For any Domain 3 design scenario, use these steps to find the answer AZ-305 expects.

  1. Read the RTO, RPO and availability requirements, since they drive the continuity design and its cost.
  2. Distinguish high availability (local-failure resilience), disaster recovery (regional recovery) and backup (data restore), and design for the right one.
  3. For backup and restore, recommend Azure Backup with the appropriate policy and vault for compute, databases and data.
  4. For regional failover, recommend Azure Site Recovery to replicate and fail over workloads to meet a low RTO and RPO.
  5. For high availability, recommend availability zones, zone-redundant services and replicas, matched to the availability target without over-provisioning. Confirm the recommended design meets every stated requirement, including compliance and cost, before committing to it.

Practice question

A critical workload must resume operations in a secondary Azure region within minutes of a regional outage, with minimal data loss. Which business continuity design should the architect recommend?

Want more like this? The AZ-305 practice test has questions for every domain.

Checklist

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Study strategy

Approach this domain by fixing the three continuity concepts firmly, since the exam tests the distinction: high availability keeps a solution running through local failures, disaster recovery recovers from a regional outage, and backup restores data. Many questions turn on choosing the right one.

Next, tie every recovery design to RTO and RPO: learn that Azure Backup protects and restores data while Azure Site Recovery replicates and fails over workloads for a low RTO, and match the design to the stated objectives and budget. Then learn high-availability design with availability zones, zone-redundant services and replicas for compute and data.

Because this is a smaller domain, do not over-invest, but do not skip it, since continuity questions are high-value and tied to clear objectives. Afterwards, move to Domain 4, designing infrastructure solutions, the largest domain. Because AZ-305 is a design exam, drill requirement-driven scenarios and justify why the recommended design beats the alternatives, anchoring on the Well-Architected and Cloud Adoption Frameworks, and review missed questions by group.

FAQ

How much of AZ-305 is Domain 3?

Design business continuity solutions is 15–20% of the exam, the smallest domain, but it covers essential recovery and availability design.

What is the difference between RTO and RPO?

RTO, the recovery time objective, is how quickly service must be restored. RPO, the recovery point objective, is how much data loss, measured in time, is acceptable.

What is the difference between Azure Backup and Azure Site Recovery?

Azure Backup protects and restores data on a schedule. Azure Site Recovery replicates workloads to a secondary region and orchestrates failover for regional disaster recovery.

What is the difference between high availability and disaster recovery?

High availability keeps a solution running through local failures, such as a datacenter fault, usually within one region. Disaster recovery recovers from a regional outage, requiring cross-region design.

Do availability zones protect against a regional outage?

No. Availability zones are within a single region and protect against datacenter failures. Surviving a regional outage requires geo-redundancy or replication to another region.

How do RTO and RPO drive the design?

Tighter objectives need faster, costlier designs such as Site Recovery or active-active, while generous objectives can be met more cheaply with backup and restore or warm standby.

How does Domain 3 connect to the rest of the exam?

It protects and keeps available the data from Domain 2 and the infrastructure from Domain 4, within the governance of Domain 1.

Other Cloud Computing certifications

Where the same subject shows up in other exams. Cards marked "Same subject" open the matching domain.

Test your Domain 3 knowledge

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