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Difficulty: HardHigh Availability, Scalability, and Elasticity

An enterprise is migrating its legacy database and web application to Azure. The database requires consistent performance during predictable month-end processing, which is achieved by upgrading the virtual machine to a size with more CPU and RAM. However, the front-end web tier must automatically handle sudden, unpredicted spikes in user traffic by adding and removing virtual machine instances, while the overall system must remain operational even if an entire datacenter within the region suffers a power outage.

Which combination of cloud characteristics matches the database adjustment, the web tier behavior, and the outage protection requirements, in that order?

  1. A
    Horizontal scaling, scalability, and high availability
  2. B
    Horizontal scaling, elasticity, and disaster recovery
  3. Vertical scaling, elasticity, and high availabilityAnswer
  4. D
    Vertical scaling, scalability, and disaster recovery

Answer

Vertical scaling, elasticity, and high availability
Upgrading the resources of an existing virtual machine (adding CPU and RAM) is vertical scaling. Automatically adding or removing virtual machine instances in response to unpredictable traffic demands is elasticity. Ensuring the application remains operational during a single datacenter failure within the same region is high availability.

Step-by-Step Solution

1
Analyze the database configuration requirement.
Upgrading the resources (CPU and RAM) of an existing virtual machine represents vertical scaling (scaling up).
Vertical scaling increases the capacity of an existing resource, whereas horizontal scaling adds more resource instances.
2
Analyze the front-end web tier requirement.
Automatically adding and removing virtual machine instances in response to unpredicted fluctuations in traffic represents elasticity.
Elasticity refers to the dynamic, automated scaling of resources in and out based on real-time demand.
3
Analyze the power outage resilience requirement.
Ensuring the application remains operational despite a local datacenter failure within the same region represents high availability.
High availability focuses on maximizing service uptime and redundancy within a region (e.g., across Availability Zones), whereas disaster recovery focuses on recovering from a catastrophic regional failure.

Key Concept

Distinguishing between vertical/horizontal scaling, elasticity/scalability, and high availability/disaster recovery.
Estimated Time:2m 0s
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Topics

High Availability, Scalability, and Elasticity

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