Azure Region Pairs
It may happen that an event is so big that it impacts a whole [[azure-region]]. In that case, [[azure-availability-zones]] are not enough to prevent data loss and application downtime. Therefore, we need to pair regions so that one acts as a fallback for the other.
Most Azure regions are paired with another region within the same geography (WestUS is paired with EastUS, for example). The minimum distance is 300 miles, so the likelihood of an event that affects both regions is small.
Advantages of Region Pairs
- If an extensive Azure outage occurs, one region out of every pair is prioritized to make sure at least one is restored as quickly as possible for applications hosted in that region pair.
- Planned Azure updates are rolled out to paired regions one region at a time to minimize downtime and risk of application outage.
- Data continues to reside within the same geography as its pair for tax- and law-enforcement jurisdiction purposes.
Backlinks
Azure Storage Redundancy Types
When creating a storage account, you must select the primary region. The paired secondary region is assigned automatically, based on [[azure-region-pairs]], and cannot be changed.
Azure infrastructure
There is a **physical structure**, in which every datacenter is located in an [[azure-availability-zones]], each Availability zone is located within an [[azure-region]], and Regions are coupled in [[azure-region-pairs]].