Consider the following operating system declaration:
robot-framework-system.scm
Description: Binary data
$ guix size `guix system build robot-framework-system.scm`
gives: store item total self /gnu/store/f9fy1b2yf1qxy523732r7z34ymwqz64b-linux-libre-5.1 241.5 241.5 21.8% /gnu/store/1lcniyxkxkh8g73zvh2gpbccvl6ggna7-locale-2.28 91.8 91.8 8.3% /gnu/store/zm3188ipzi262s0m8bxm24br77yh9pd8-python-3.7.0 183.0 74.6 6.7% /gnu/store/h8l1pby3cm6b4fxsfwwr65b4d1hyh6cs-python-3.7.0 183.0 74.6 6.7% /gnu/store/wqr8rwnwpmag01i6kb0laf62vsqnhrxy-python-3.7.0 183.0 74.6 6.7% /gnu/store/b7fqhszxl02g6pfm3vw6b3cjz472qrly-python-3.7.0 182.8 74.6 6.7% [...] total: 1106.3 MiB But, $ guix size `guix system --no-grafts build robot-framework-system.scm` store item total self /gnu/store/f9fy1b2yf1qxy523732r7z34ymwqz64b-linux-libre-5.1 241.5 241.5 28.4% /gnu/store/1lcniyxkxkh8g73zvh2gpbccvl6ggna7-locale-2.28 91.8 91.8 10.8% /gnu/store/b7fqhszxl02g6pfm3vw6b3cjz472qrly-python-3.7.0 182.8 74.6 8.8% /gnu/store/ybglr7nfs8v9kpnm8vf4drg3gafnvd15-guile-static-stripped-2.2.4 45.9 45.9 5.4% total: 851.2 MiB Conclusion: the size of grafts is added multiple times even though they should be very light on disk usage given that they are mostly hard links to the original, ungrafted output.
