Service Applications and MinRoles
In a single server Farm, you might decide to have everything running on that one server.
On a multi-server Farm, services can be started or stopped on particular servers in your Farm to support scale out.
From SharePoint 2016 onwards, you can define MinRoles.
That’s the smallest set of services that you require to be switched on for a tier of servers.
A MinRole can then be allocated to specific servers.
SharePoint now takes care of making sure the right services are started.
To load balance Services without MinRoles, you just start an instance of your Service on a new Server.
However, with MinRoles, you just need to associate your MinRole with the server.
SharePoint will then start and load balance the requisite Services without any further work on your part.