Comment on When using rsync to backup my /home folder to an external 1TB SSD, I run out of space, how??
sbeak@sopuli.xyz 10 hours agousing du -hsc returns 384G with /home/sbird, and 150G inside the external SSD (when it does not have any of the files transferred with rsync)
SlurpingPus@lemmy.world 10 hours ago
Well, that’s not what I meant. If you have directories with torrents or VMs,
dumight report different size for those directories on the source and target disks. Then it might’ve meant that those are the culprits.With just the source disk, you can check
du -hsc dirnameversusdu -hsc --apparent-size dirnameto check if the disk space used is much smaller than the ‘apparent size’, which would mean there are sparse files in the directory, i.e. not fully written to disk. rsync would copy those files to full ‘apparent size’.As mentioned elsewhere, btrfs might also save space on the source disk by not writing duplicate files multiple times — but idk if
duwould report that, since it’s specific to btrfs internals.