If I have 2 VMs in 2 different regions

Question

If I have 2 VMs in 2 different regions and I have the same configurations for both fully what all differences can I see in both VM? and what criteria should I follow to select the region to choose to run the VM?

Answer 1

Hello Allen ,

Thanks for reaching out to Microsoft Q and A Forum ,

If you have two VMs in different Azure regions with identical configurations, here are the key differences you may observe and the criteria for selecting the right region:

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Potential Differences Between the Two VMs

Even with the same configuration, the following factors may vary:

1. Latency & Performance
   • VMs in different regions experience different network latencies depending on user proximity and Azure backbone connectivity.
   • The distance from your application users or on-premises data center affects speed.
2. Pricing Differences
   • VM pricing varies by region, including compute, storage, bandwidth, and reserved instances.
   • Example: East US might be cheaper than West Europe due to regional demand.
3. Service Availability & Quotas
   • Some VM series and sizes (e.g., latest GPU-based VMs) may not be available in all regions.
   • Azure enforces regional quotas for resources like vCPU limits.
4. Storage Replication & Latency
   • Storage performance may differ based on the region's datacenter capabilities and replication settings (LRS, ZRS, GRS).
   • Cross-region disk replication might introduce higher latency.
5. Compliance & Data Residency
   • Certain regions follow specific regulatory compliance (e.g., GDPR in Europe, HIPAA in the US).
   • Data residency laws may require storing data in a specific region.
6. Availability Zones (AZs) Support
   • Some regions have more Availability Zones (e.g., 3 AZs vs. only 1).
   • Higher AZs improve resilience against outages.

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Criteria for Choosing an Azure Region for a VM

When selecting a region, consider these factors:

Latency & Proximity – Choose the closest region to users for better performance.
Cost Optimization – Compare VM pricing in different regions.
Availability Zones – Pick a region with more AZs for higher availability.
Service Availability – Ensure required VM sizes, GPU instances, or other features are available. Regulatory Compliance – Select a region that aligns with data residency laws.
Disaster Recovery Needs – Use paired regions for redundancy (e.g., East US ↔ West US).

🔹 Best Practice: Use Azure Region Picker (https://azure.microsoft.com/en-us/global-infrastructure/geographies/) to compare VM availability, cost, and compliance per region. 🚀

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