In order to transition to macos to linux I copied files (using rsync) from my macos to an exfat formatted external hard drive and copied those data (using rsync again) from the exfat formatted external hard drive to the Ubuntu 22.04.
Among one of the directory to be copied, its size was 70GB on the exfat external hard drive, however, this same directory was only 23GB on both the linux system and the macos system. I looked deeper into subdirectories of this directory and found that a directory containing many (600) .jpg files were 4KB on both the macos and linux files but were 128KB on the exfat hard drive. So that mean that the files were “inflated” by a factor 32 when copied from the macos to the exfat external hard drive and the (rightfully…) deflated from the exfat external hard drive to the linux system! How is this possible?

Although not necessary to understand the question, this phenomenon was discovered while facing problem when attempting to transition from macos to linux which triggered those 2 previous questions:

• https://askubuntu.com/questions/1513607/copying-a-specific-70gb-directory-from-a-backup-makes-the-system-crash-while-it/1515558#1515558
• https://askubuntu.com/questions/1513330/copying-files-cp-and-rsync-from-rom-macos-formatted-exfat-sytematically-crashe