How to use deduplication for cleaning up several harddiscs?

General Topics
1

I am new with kopia and I am very interested to use it in a first step for cleaning up several harddiscs. They often contain duplicate data. If I use kopia with its deduplication function, I could backup and deduplicate all these data.

And after that, it would be ideal, to copy back from this backup in a way, that only one version of each file would be restored on one single harddisc. This would be a tremendous simplification against sorting out duplicates manually with a file manager.

Do you think, this is deduplication and restoring is possible?

2

Nope.

This is not what kopia is for. It only deduplicates stored content in order to minimise used storage space for your backups. All process is transparent from user perspective and does not give you any information about what is duplicate and what is not.

What you need is specialised deduplication software. Good example I would recommend is GitHub - pkolaczk/fclones: Efficient Duplicate File Finder