

You can rerun the du command with --count-links to count hardlinks multiple times. If that shows >780GiB you have a lot of hardlinks somewhere, which you can narrow down by rerunning the command on each of the subdirectories in your home directory.
Your options would be to delete the hardlinks to decrease your total file size, exclude them from the rsync with --exclude, or repartition your SSD to a filesystem that supports hardlinks.





That’s odd, maybe it has to do with symlinks? Adding
--dereferenceto theducommand will count the file size of the files referenced by symlinks. If that doesn’t show anything abnormal, I’d compare the directory sizes between your home directory and the rsync backup and try to find where they differ significantly. If it does show a much larger size, narrow down the location of the relevant symlinks (may be a hidden directory) and either delete them or exclude them from the rsync.