How Big the Storage Drive of duplicati App Should Be?

As per question, how big the storage drive that holds onto the dupliati app/docker and databases (not the folders/drives to be backed up, not the backup destination) should be?

I am getting some “Out of Storage on Device” error messages and saw that the storage drive for the app and databases is getting full; will like to roughly know how much more to get so that I can plan upgrades

Are you sure, that it is duplicati that is filling your drive?

I guess there will be no answer to your question, as it depends on the size of your backup and many other factors,

I am sure it is considering that it is literally the only thing running on the server

Kinda resolved it by clearing out all unused databases. I could see the used space of that drive fluctuating during restoration