Once in Central US Region in San Antonio there was Weather breakout that caused the Power interruptions resulted in Cooling System failure and Hardware failure across Racks. This resulted in outage on several VMs in the region and it had taken around two days for Microsoft to bring the entire resources up.
The lesson learned by Microsoft from the incident is to introduce Availability Zones in the each region which was way back implemented in AWS to have increased availability of the VMs.
As per Availability Zone in Azure Regions are broken down into at least 3 separate Availability Zones. Each Availability Zone will be distinct, possessing its own power, cooling, high speed, low latency connections.
So, if you’re deploying a web tier consisting of 2 VMs in Ireland, you can now make sure that VM1 is placed in Availability Zone 1 and VM2 is placed in Availability Zone 2. If zone 1 was to fail, you (and your customers) would still be able to access VM2 in AZ2.
So, if you’re deploying a web tier consisting of 2 VMs in Central US, you can now make sure that VM1 is placed in Availability Zone 1 and VM2 is placed in Availability Zone 2. If zone 1 was to fail, you (and your customers) would still be able to access VM2 in AZ2.
This means your service won’t have to run from a separate Azure region and will be faster as a result. This is especially useful if your customers are concentrated in a single region rather than multiple Region.
Loadbalancer shall be used to connect the Application Servers. The availability range shall be used when picking up servers regions for Configuring Always on for SQL Server, etc.
As of now Availability Zones are not implemented across all regions. Implemented Regions are below.
- Central US
- East US 2 (Preview)
- France Central
- North Europe
- Southeast Asia
- West Europe
- West US 2
Below screenshot would guide to Set up Availability Zone. Availability Zone should be Set while the VM is configured. Zones numbered from 1 to 3 and you can configure the VMs across theses three Zones.
CloudToon 
Leave a comment