When running
rsync -Paz /home/sbird "/run/media/sbird/My Passport/sbird"
As told by someone, I run into a ran out of storage error midway. Why is this? My disk usage is about 385 GiB for my home folder, and there is at least 800 GiB of space in the external SSD (which already has stuff like photos and documents). Does rsync make doubly copies of it or something? That would be kind of silly. Or is it some other issue?
Note that the SSD is from a reputable brand (Western Digital) so it is unlikely that it is reporting a fake amount of storage.
Let’s back up and check your assumptions: How did you check that the disk usage of your home folder is 385GiB and that there are 780GiB of free disk space on your external drive?
Using du -sh --apparent-size /home/sbird returns 382G, with external SSD 129G (as expected)
Is your external SSD partitioned into multiple drives? Are you saying that your SSD is reported to be 129GB by the OS?
129G used (as in the files that were there before rsync)
Checking “properties” using Dolphin. Could that be incorrect?
I’d say you can trust that.