When PCF Elastic Runtime has already been installed, you will not be able to automatically change your initial system databases configuration option, for example: changing from an embedded system database to an external database.
The reason for making this change is that PCF will not automatically migrate your data to the newly selected option.
Current options are the following:
Configurations should only be made on the initial installation of Elastic Runtime and you should NOT change anything on this section (System Databases Configuration) when upgrading.
For more details on System Databases Configuration please refer to the documentation here: https://docs.pivotal.io/pivotalcf/customizing/config-er-vmware.html#er-db-config