The first drive's backup occupies less space on the second drive.
The first drive's backup occupies less space on the second drive.
I possess two storage units, each with identical capacity and formatted using ext4. The confusing aspect is that the files occupy less space on the backup drive—despite being a direct 1:1 rsync copy and having the same logical size. What's happening? Volume names differ: storage2 versus backup2.
Both sides contain identical file counts. Rsync operates without reading what it can't access, ensuring consistency.
Dolphin reports identical file counts, folders, and total size, yet he questions the backup size being smaller. He wonders about counting files via the console and suspects Dolphin might be right. I back up as root to confirm permissions aren’t a problem, though ownership should remain consistent.
Running the command "du -sh --apparent-size /mnt/storage2 /mnt/backup2" will display the sizes in a human-readable format. The --apparent-size option shows the size as it appears to the user, not the actual disk usage. Check the documentation at https://linux.die.net/man/1/du for details.
The firmware handling data volume calculations might be communicating differently with the kernel and filesystem.
It's more likely due to scattered files and indirect blocks. When a file is saved and read, it reserves extra space for unused areas and metadata. During copying or moving, data may get lost and empty spots aren't properly assigned. This information doesn't impact the file's content but influences the filesystem and overall disk usage. The "--apparent-size" option in du adjusts for this, showing an estimate of the actual storage needed.