Ask HN: How do you save and archive files with metadata?

By metadata, I mean tags, notes or even links to other resources.

Do you use the capabilities of your file-system? If so, how do you make sure they are backed up correctly? Or, do you use an application, a database or a service?

I was thinking about writing an application which saves files to many "storage providers" and associates them with other data, but then I thought, this must have been done before.

I would be okay by using just a postgres db for this purpose but I was afraid this would complicate and slow down the backup process and saving files to the db is a controversial subject.

I'd love to hear what works for HN.