DP-300 Practice Question: Plan and configure high availability and disaster recovery
You manage a SQL Server 2019 Always On availability group on Azure Virtual Machines. The availability group has two synchronous replicas in an availability set and one asynchronous replica in a different Azure region. During a planned maintenance window, you need to patch the operating system on the primary replica with minimal downtime and no data loss. What should you do first?
⚠ Common exam trap
The trap here is assuming that patching the primary in place or failing over to an asynchronous replica is acceptable, when only a manual failover to a synchronous secondary guarantees no data loss and minimal downtime.
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
✓
Perform a manual failover of the availability group to the synchronous secondary replica.
To patch the primary replica with no data loss and minimal downtime, you must first move the primary role to a synchronous secondary replica using a manual failover. Because the secondary is synchronized, the failover is seamless and lossless. After the failover, the former primary becomes a secondary and can be patched while the availability group remains online and accessible through the listener.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Take the primary replica offline and patch it, then bring it back online.
Why it's wrong here
Taking the primary offline causes an outage and the availability group will not have a primary, making the databases unavailable. This violates the minimal downtime requirement. Patching should be done on a node that is not currently the primary, after moving the primary role elsewhere.
- ✗
Fail over to the asynchronous replica in the remote region.
Why it's wrong here
Failing over to an asynchronous replica can result in data loss because the replica may not have received all recent transactions. Additionally, the remote region replica may have higher latency and is not configured for synchronous commit, so it does not guarantee zero data loss. This option introduces risk and does not meet the no-data-loss requirement.
- ✓
Perform a manual failover of the availability group to the synchronous secondary replica.
Why this is correct
Performing a manual failover to a synchronous secondary ensures no data loss because the secondary is synchronized, and it moves the primary role away from the node being patched. This allows you to patch the former primary while the availability group remains online and the application continues to use the listener. It is the standard first step for patching with minimal downtime and no data loss.
- ✗
Set the availability group to asynchronous commit mode and then patch the primary.
Why it's wrong here
Changing to asynchronous commit mode does not move the primary role and does not prevent downtime if you patch the primary in place. It also risks data loss if a failover occurs while in asynchronous mode. The correct approach is to move the primary role to a synchronized secondary before patching.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Microsoft exam blueprint
This DP-300 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-300 exam.