We have quite a few very large ONTAP "filservers." Previously we would use Treesize Pro to help manage the content and we continue to use that now but I am wondering is there a better tool? What are other people using to manage the file data?
Check out Varonis. They have a tight partnership with NetApp. It's mostly used as a file access auditing tool, but they do have other features related to filesystem consumption metrics that you're looking for. https://www.varonis.com/products/data-transport-engine/
Varonis leverages fpolicy, so it doesn't necessarily have to traverse the directory structure. Works much faster than something like Tree Size or FolderSizes.