Note that some services or features are only available in certain regions
US DoD and Gov are separate datacenters specifically for government applications
China datacenters are managed by 21Vianet
Geographies are defined by geopolitical boundaries or county borders. This has the benefits:
Allow customers with specific compliance to keep their data close
Ensure data residency, sovereignty, compliance and resiliency requirements are honoured within geographical boundaries.
Ensure fault tolerance.
Azure has the following geographies:
Americas
Europe
Asia Pacific
Middle East and Africa
This means that if one zone goes down, the other continues working
Azure services that support availability zones fall in two categories:
Zonal services - Pin the resource to a specific zone
Zone-redundant services - Platform replicates automatically across zones
Advantages of region pairs:
If there’s a large azure outage, one region out of every pair is prioritized to be restored as quickly as possible
Planned Azure updates are rolled out to paired regions one region at a time to minimise downtime and risk of application outage
Data continues to reside in the same geography as its pair for compliance purposes
An SLA provides performance targets for a product or service
Typical SLA ranges from 99.9% to 99.999%
Define how Microsoft will respond if a product fails to perform to its SLA spec.
The lower the uptime percentage, the greater the service credit percentage given
Calculating the SLA of two services together is just multiplying them
However if you install redundancy such as two databases, the SLA is calculated with
And this result is then multiplied by the SLA of the other component to get the SLA
Maximizing availability requires implementing measures to prevent service failures. However this can be difficult and expensive.
You need to ensure that the minimum SLA in your system is one that you are happy with your service performing at.