Merge pull request #104780 from stefsch/patch-16

Minor tweaks to align with overall Azure guidance on AZs

Author: Court72

articles/reliability/migrate-app-service-environment.md

@@ -19,7 +19,7 @@ This guide describes how to migrate an App Service Environment from non-availabi
 
 Azure App Service Environment can be deployed across [availability zones (AZ)](../reliability/availability-zones-overview.md) to help you achieve resiliency and reliability for your business-critical workloads. This architecture is also known as zone redundancy.
 
-When you configure to be zone redundant, the platform automatically spreads the instances of the Azure App Service plan across all three zones in the selected region. This means that the minimum App Service Plan instance count will always be three. If you specify a capacity larger than three, and the number of instances is divisible by three, the instances are spread evenly. Otherwise, instance counts beyond 3*N are spread across the remaining one or two zones.
+When you configure to be zone redundant, the platform automatically spreads the instances of the Azure App Service plan across three zones in the selected region. This means that the minimum App Service Plan instance count will always be three. If you specify a capacity larger than three, and the number of instances is divisible by three, the instances are spread evenly. Otherwise, instance counts beyond 3*N are spread across the remaining one or two zones.
 
 ## Prerequisites
 
@@ -44,7 +44,7 @@ If you want your App Service Environment to use availability zones, redeploy you
 
 Traffic is routed to all of your available App Service instances. In the case when a zone goes down, the App Service platform will detect lost instances and automatically attempt to find new replacement instances and spread traffic as needed. If you have [autoscale](../app-service/manage-scale-up.md) configured, and if it decides more instances are needed, autoscale will also issue a request to App Service to add more instances. Note that [autoscale behavior is independent of App Service platform behavior](../azure-monitor/autoscale/autoscale-overview.md) and that your autoscale instance count specification doesn't need to be a multiple of three. It's also important to note there's no guarantee that requests for additional instances in a zone-down scenario will succeed since back filling lost instances occurs on a best-effort basis. The recommended solution is to create and configure your App Service plans to account for losing a zone as described in the next section.
 
-Applications that are deployed in an App Service Environment that has availability zones enabled will continue to run and serve traffic even if other zones in the same region suffer an outage. However it's possible that non-runtime behaviors including App Service plan scaling, application creation, application configuration, and application publishing may still be impacted from an outage in other Availability Zones. Zone redundancy for App Service Environments only ensures continued uptime for deployed applications.
+Applications that are deployed in an App Service Environment that has availability zones enabled will continue to run and serve traffic if a single zone becomes unavailable.  However it's possible that non-runtime behaviors including App Service plan scaling, application creation, application configuration, and application publishing may still be impacted from an outage in other Availability Zones. Zone redundancy for App Service Environments only ensures continued uptime for deployed applications.
 
 When the App Service platform allocates instances to a zone redundant App Service plan, it uses [best effort zone balancing offered by the underlying Azure Virtual Machine Scale Sets](../virtual-machine-scale-sets/virtual-machine-scale-sets-use-availability-zones.md#zone-balancing). An App Service plan will be "balanced" if each zone has either the same number of VMs, or +/- one VM in all of the other zones used by the App Service plan.
 
@@ -101,4 +101,4 @@ There's a minimum charge of nine App Service plan instances in a zone redundant
 ## Next steps
 
 > [!div class="nextstepaction"]
-> [Azure services and regions that support availability zones](availability-zones-service-support.md)
+> [Azure services and regions that support availability zones](availability-zones-service-support.md)