AZ-104 Question 131
Single answerYou are deploying a new multi-tier application in Azure that must remain highly available even in the event of a datacenter failure. Additionally, the solution must provide at least a 99.99% service-level agreement (SLA) at the virtual machine level. Which deployment strategy should you implement?
- A
Deploy multiple virtual machines in a single Availability Set
- B
Deploy multiple virtual machines in separate Availability Zones within the same region
- C
Deploy multiple virtual machines in different resource groups
- D
Deploy multiple virtual machines in a single Virtual Machine Scale Set using ephemeral OS disks
Show answer and explanation
Correct answer: B
Explanation
Availability Zones provide independent power, cooling, and networking, ensuring resilience even if one entire facility goes down. Placing multiple VMs across separate Availability Zones in the same region meets both the high availability and the 99.99% SLA requirements.
- A. Incorrect.
An Availability Set helps with host-level faults but does not protect against a full datacenter outage. Availability Sets provide a 99.95% SLA when configured properly, not 99.99%.
- B. Correct.
Placing VMs in different Availability Zones ensures redundancy across physically separate locations in a region, protecting from complete datacenter failures. This configuration meets the 99.99% SLA requirement for VMs.
- C. Incorrect.
Different resource groups alone do not provide high availability or fault domain separation; they are more about logical organization of resources.
- D. Incorrect.
A Virtual Machine Scale Set can help with autoscaling, and ephemeral OS disks can improve performance, but deploying all VMs in a single Scale Set does not inherently protect against a full datacenter outage.