just comparing the subvolume with its snapshot with btrfs send -p /example/subvol /snapshot/of/example/subvol >examplediff.btrfs.

From man btrfs-send

generate a stream of instructions that describe changes between two subvolume snapshots

Thanks for btdu, it seems useful as ‘btrfs fi du’ probably doesn’t account for compression, will check it out sometime.

Thanks that helped. I have one snapshot of home. Size of diff between btrfs subvolume and snapshot is 11GiB and btrfs fi du -s / is 72GiB, making 83GiB (closer to btrfs fi df /).

oh shit I forgot to set up subvolumes

lol

I’m also planning on using its subvolume and snapshot feature. since zfs also supports native encryption, it’ll be easier to manage subvolums for backups