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How Do Availability Sets and Availability Zones Provide VM High Availability Within an Azure Region?
Prepare for AZ-500 exam by learning the key differences between Availability Sets and Availability Zones for achieving high availability for VMs within an Azure region. Understand Update Domains, Fault Domains, and when to use each solution for intra-region resilience.
Question
To achieve high availability for VMs within an Azure region, which of the following options are available?
A. Availability Sets and Azure Site Recovery
B. Azure Site Recovery and Availability Zones
C. Availability Sets and Availability Zones
D. Availability Sets, Availability Zones, Azure Site Recovery
Answer
C. Availability Sets and Availability Zones
Explanation
The correct answer is C. Availability Sets and Availability Zones are the two primary architectural constructs designed to provide high availability for virtual machines within a single Azure region.
Both Availability Sets and Availability Zones enable VM high availability within an Azure region.
Availability Sets
An Availability Set is a logical grouping of VMs that allows Azure to understand how your application is built to provide redundancy and availability. It protects against failures within a single datacenter by distributing VMs across different physical hardware.
- Fault Domains: These represent groups of VMs that share a common power source and network switch. An Availability Set distributes your VMs across multiple fault domains (up to 3) to protect against a localized hardware or power failure affecting a single server rack.
- Update Domains: These represent groups of VMs and underlying physical hardware that can be rebooted at the same time for planned maintenance. An Availability Set spreads your VMs across multiple update domains (up to 20) to ensure that only a subset of your VMs are offline at any given time during Azure platform updates.
- Scope: Protects against hardware failures and planned maintenance events within a single datacenter.
Availability Zones
Availability Zones are physically separate datacenters within a single Azure region, each with independent power, cooling, and networking. This design provides a higher level of availability by protecting applications and data from a datacenter-level failure.
- How it Works: To achieve high availability, you deploy instances of your application (e.g., two or more VMs) across two or more Availability Zones. If one zone experiences an outage, your VMs in the other zones remain operational.
- Scope: Protects against the failure of an entire datacenter within a region. Because of this, it offers a higher SLA (99.99%) than Availability Sets (99.95%).
Why Azure Site Recovery is Incorrect for This Scenario
Azure Site Recovery (ASR) is a disaster recovery (DR) service, not a high availability solution. Its primary purpose is to orchestrate the replication of VMs from a primary Azure region to a secondary Azure region.
- High Availability vs. Disaster Recovery: High availability provides automatic failover within a region to protect against localized failures with minimal downtime. Disaster recovery involves failing over to a different region in response to a large-scale regional outage. ASR is the tool for DR, while Availability Sets and Zones are the tools for HA. Therefore, options A, B, and D are incorrect because they include a DR service as a HA solution.
Microsoft Certified Azure Security Engineer Associate AZ-500 certification exam assessment practice question and answer (Q&A) dump including multiple choice questions (MCQ) and objective type questions, with detail explanation and reference available free, helpful to pass the Microsoft Certified Azure Security Engineer Associate AZ-500 exam and earn Microsoft Certified Azure Security Engineer Associate AZ-500 certification.