One drive for business will create a cache of all the files it works on as well as the user's workable directory.
This means that a 100gb onedrive for business will require 200gb of storage unless the files are deleted regularly.
The below Github link offers a .MSI file that will install a service that can clean out the cache as the files in there are no longer needed. The instructions for setting it up are included in the directory.
Download for the service installer https://github.com/ajtowf/OfficeCacheCleaner/blob/master/dist/OfficeCacheCleaner.msi
Instructions to configure the service prior to starting it https://github.com/ajtowf/OfficeCacheCleaner/blob/master/README.md