Reported by Florian Pelz: https://lists.gnu.org/archive/html/guix-devel/2020-11/msg00326.html. * gnu/installer/utils.scm (call-with-time): New procedure, (let/time): new macro. * gnu/installer/parted.scm (with-delay-device-in-use?): Increase the retry count to 16. (non-install-devices): Remove the call to with-delay-device-in-use? as it doesn't return the expected result, and would block much longer now. (free-parted): Log the time required to sync each device.