btdu

Something like that exists for btrfs; it's called bdtu. It has the accuracy/time trade-off you're interested in, but the implementation is quite different. It samples random points on the disk and finds out what file path they belong to. The longer it runs the more accurate it gets. The readme is good at explaining why this approach makes sense for btrfs and what its limitations are. https://github.com/CyberShadow/btdu

This one? https://github.com/CyberShadow/btdu Seems to be specific for btrfs

If you use a Btrfs filesystem with snapshots, I can recommend Btdu as an alternative. Advantage: Can handle duplicate files (snapshots), which however only occupy 1x disk space. https://github.com/CyberShadow/btdu

Very cool. In my mind, ncdu is "the" TUI tool for disk usage analysis. I copied its UI in making btdu, a similar tool specifically for btrfs filesystems. Written in D! https://github.com/CyberShadow/btdu/blob/master/ARCHITECTURE...