We can’t change a database maximum size in the portal (as of December 2016).
Using ARM template, it is easy to change the parameter. Here, let’s simply show how we would change it for an existing database.
Building on the example we gave in a previous article, we can easily grab the Pool-A-Db0 database in resource group DBs and server pooldemoserver:
Click through for all the details. I highlighted this snippet as another point that the most important language for a Windows administrator to learn nowadays is Powershell.