add comment about configuring identical upstreams in the secondary region

Author: kuthiala

content/nginxaas-azure/disaster-recovery.md

@@ -8,7 +8,7 @@ type:
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-This guide describes how to configure disaster recovery (DR) for F5 NGINX as a Service for Azure deployments in separate (ideally [paired](https://learn.microsoft.com/en-us/azure/reliability/regions-paired)) Azure regions, ensuring upstream access remains available even if a region fails. The deployment architecture ensures users can access backend application servers (upstreams) continuously from an alternative region if the primary region becomes unavailable. The solution leverages Terraform, Azure Traffic Manager, Azure Virtual Network (VNet) peering, and unique subnets to support failover.
+This guide describes how to configure disaster recovery (DR) for F5 NGINX as a Service for Azure deployments in separate (ideally [paired](https://learn.microsoft.com/en-us/azure/reliability/regions-paired)) Azure regions, ensuring upstream access remains available even if the primary NGINXaaS deployment in a region fails. The deployment architecture ensures users can access backend application servers (upstreams) continuously from an alternative region if the primary NGINXaaS deployment becomes unavailable. The solution leverages Terraform, Azure Traffic Manager, Azure Virtual Network (VNet) peering, and unique subnets to support failover.
 
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@@ -197,6 +197,7 @@ resource "azurerm_linux_virtual_machine" "nginx_upstream_vm" {
   )
 }
 ```
+> **Note**: As a best practice, you should have identical upstreams in the secondary region as your primary region. This will ensures that you are completely protected if the primary region entirely fails in the event of a region-wide disaster.
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 ### Step 3: Peer the VNets