@IanGabes - apologies, currently they are undocumented internal fields that we mention only when we need to help people work around limitations in 1.0
With each minor release we are adding curated and documented models to the API for the settings that are currently only exposed via this "advanced" page
In the meantime do ask here and we'll dispense "tribal knowledge" on the fields with the proviso that they are not considered stable across version releases
The fs_multiplier field should be an integer and is mulitplied by the cluster capacity (in GB) to provide the disk quota - let me know if you need any more details on that
An example of its use (inserted at the top level of the "Data" field under config/advanced
"overrides": {
"quota": {
"fs_multiplier": 35
}
},