Application Gateway Scaling ​

Scaling Application Gateway and WAF v2 ​

Application Gateway and WAF can be configured to scale in two modes:

Autoscaling: With autoscaling enabled, the Application Gateway and WAF v2 SKUs scale up or down based on application traffic requirements. This mode offers better elasticity to your application and eliminates the need to guess the application gateway size or instance count. This mode also allows you to save cost by not requiring the gateway to run at peak provisioned capacity for anticipated maximum traffic load. You must specify a minimum and optionally maximum instance count. Minimum capacity ensures that Application Gateway and WAF v2 don't fall below the minimum instance count specified, even in the absence of traffic. Each instance is roughly equivalent to 10 additional reserved Capacity Units. Zero signifies no reserved capacity and is purely autoscaling in nature. You can also optionally specify a maximum instance count, which ensures that the Application Gateway doesn't scale beyond the specified number of instances. You will only be billed for traffic served by the Gateway. The instance counts can range from 0 to 125. The default value for maximum instance count is 20 if not specified.

Manual: You can alternatively choose Manual mode where the gateway doesn't autoscale. In this mode, if there is more traffic than the Application Gateway or WAF can handle, it could result in traffic loss. With manual mode, specifying instance count is mandatory. Instance count can vary from 1 to 125 instances.