Question

Difficulty: MediumCompute Virtualization Solutions

An enterprise is planning to migrate a critical, steady-state production ERP system to Azure. The system consists of two main components: a stateful database tier that runs continuously and requires guaranteed compute availability, and a stateless web server tier that must scale dynamically to handle variable user traffic. Both tiers must be designed to minimize compute costs over a multi-year period, but the solution must guarantee that no virtual machines are subject to unexpected eviction or disruption. Which two virtual machine options or pricing models should you recommend to meet these requirements?

  1. Azure Reserved Virtual Machine Instances for the database tierAnswer
  2. Virtual Machine Scale Sets with Flexible orchestration for the web tierAnswer
  3. C
    Azure Spot Virtual Machines for the database tier
  4. D
    Azure Spot Virtual Machines for the web tier

Answer

Azure Reserved Virtual Machine Instances for the database tier, and Virtual Machine Scale Sets with Flexible orchestration for the web tier
For the database tier, Azure Reserved Virtual Machine Instances are the correct choice because they provide cost optimization for a 24/7 steady-state workload without any risk of eviction. For the web tier, Virtual Machine Scale Sets with Flexible orchestration are the correct choice because they enable dynamic scaling and high availability across multiple availability zones for stateless workloads.

Step-by-Step Solution

1
Analyze the database tier requirements
The database is a steady-state workload that runs 24/7 and cannot tolerate eviction. Azure Reserved Instances provide cost savings for predictable, continuous compute needs without eviction risk.
Reserved Instances offer up to 72% cost savings over pay-as-you-go for workloads committed to 1 or 3 years.
2
Analyze the web tier requirements
The web tier requires dynamic scaling to handle variable user traffic. Virtual Machine Scale Sets allow for automated autoscaling. Flexible orchestration mode provides high availability and VM control.
Virtual Machine Scale Sets allow stateless web tiers to scale out and in based on demand.
3
Evaluate and eliminate Spot VM options
Spot VMs are eliminated because they can be evicted with a 30-second warning, violating the zero-eviction SLA requirement for both tiers.
Spot VMs are designed for interruptible workloads, not critical production systems.

Key Concept

Selecting Azure compute and pricing options based on workload predictability, scaling requirements, SLA, and cost constraints.
Estimated Time:1m 30s
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