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Azure Availability Zones

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Overview

 Azure Availability Zones are designed to reduce a single point of failure given a specific IaaS scenario, mainly described as:

“fault-isolated locations within an Azure region, providing redundant power, cooling, and networking. Availability Zones allow customers to run mission-critical applications with higher availability and fault tolerance to datacenter failures.”.

 

https://wikiazure.azureedge.net/wp-content/uploads/2017/09/Azure-AvailabilityZones-Infographic-wikiazure.png

 

 Download Infographic

 

 

The Difference Between Availability Sets – Availability Zones – Region Pairs

 

 

https://wikiazure.azureedge.net/wp-content/uploads/2017/09/Avzones-wikiazure-2.png

 

 

Feature Capability / Provide
Availability Sets High-availability protection from hardware, network, and power failures in a DC
Availability Zones High-availability protection against the loss of entire DC(s)
Region pairs Disaster Recovery that protects from the loss of an entire region

 

Top Features Of Azure Availability Zones:

 

  • Availability Zones (AZ) are physically separated locations within a specific Azure region
  • Each AZ has independent power, network, and cooling
  • AZ locations are chosen based on a per-region risk assessment
  • AZs are designed to reduce single points of failure in the platform

 

How Can Azure Availability Zones Help You?

 

Let's discuss 3 approaches where Availability Zones can help you increase resiliency:

  • High-availability and Disaster Recovery
  • Low Latency for synchronous replication
  • Protection from data center-level failure

 

High-Availability and Disaster Recovery:

Native HA and DR support through Availability Zones and Regional pairs. Each AZ enabled region has a minimum of three zones. All regions have one region pair providing data replication with data residency.

https://wikiazure.azureedge.net/wp-content/uploads/2017/09/HA-DisasterRecovery-wikiazure.png

 

Low Latency for synchronous replication:

Zones are close enough to each other for synchronous replication, meaning high-availability for applications and minimal data loss.

 

https://wikiazure.azureedge.net/wp-content/uploads/2017/09/DecreasedLatency-wikiazure.png

 

Protection from data center-level failure:

Each zone is physically separated with independent power, network, and cooling and logically separated through zone-isolated services.

 

https://wikiazure.azureedge.net/wp-content/uploads/2017/09/Protection-AvailabilityZones-wikiazure.png

 

Example Of A Web App Utilizing Azure Availability Zones

https://wikiazure.azureedge.net/wp-content/uploads/2017/09/ZoneRedundantLB-wikiazure.png

https://wikiazure.azureedge.net/wp-content/uploads/2017/09/ZoneRedundant2LB-wikiazure.png

 

Considerations:

  • Each zone consists of one or more data centers within a region
  • You can load balance across all your VMs deployed in Availability Zones enabling scenarios with zonal frontends and cross-zone load balancing for the backend
  • For regions that do not support Availability Zones,  Availability Sets should still be leveraged for HA (and to get SLA).
  • Availability Zones protect against local failures and covers a broader set. Planned maintenance just launched as a service and can be a substitute for update domains.
  • Availability Sets and Availability Zones are not supported at the same time.
  • In the case of Always On the SQL engineering team recommends you spread your nodes equally across the three zones for the highest availability

Documentation

Don´t forget to check out the Technical Documentation here! 

http://aka.ms/azoverview

  

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