In a nutshell: • Files < 1KiB contribute to 0.3% of the space savings; • Files < 4KiB contribute to 2.5% of the space savings; • Files < 256KiB contribute to 42% of the space savings. You can create this plot with: --8<---------------cut here---------------start------------->8--- (make-scatter-plot #:title "Contribution to space savings" #:write-to-png "/tmp/space-saving-contribution.png" #:chart-width 1000 #:y-axis-label "contribution (%)" #:x-axis-label "size (B)" #:log-x-base 2 #:min-x 513 #:data (let ((total (saved-space l))) `(("contribution" ,@(map (lambda (size) (cons size (/ (saved-space (filter (lambda (file) (< (deduplicated-file-size file) size)) l)) total .01))) (map (cut expt 2 <>) (iota 12 10 1))))))) --8<---------------cut here---------------end--------------->8--- You can also compute individual points like this: --8<---------------cut here---------------start------------->8--- scheme@(guile-user)> (/ (saved-space (filter (lambda (file) (< (deduplicated-file-size file) 1024)) l)) (saved-space l) 1.) $60 = 0.0034284626558736746 scheme@(guile-user)> (/ (saved-space (filter (lambda (file) (< (deduplicated-file-size file) 4096)) l)) (saved-space l) 1.) $62 = 0.025190871178467848 scheme@(guile-user)> (/ (saved-space (filter (lambda (file) (< (deduplicated-file-size file) (expt 2 18))) l)) (saved-space l) 1.) $65 = 0.42411104869782185 --8<---------------cut here---------------end--------------->8--- Choosing a deduplication threshold of 2KiB or 4KiB would have a negligible impact on disk usage on my machine. Thanks, Ludo’.