You can manage how your fleet scales per region with scaling settings. There are two scaling settings available per region: the minimum available servers and the maximum servers. Together, these scaling settings control the size of the available servers buffer.
Minimum available servers
The minimum available servers scaling setting controls the minimum number of servers available in a region at a time. You can use the minimum servers setting value to ensure availability in a region to allow new users to use your application.
The maximum servers scaling setting controls the maximum number of available servers in a region at a time. It doesn't set an upper bound on the total number of servers in a region.