I am confused by the benefits of rsync (3.1.1) if there is no daemon running remotely, e.g. copying from a drive mounted via SMB2 (via a VPN) to an external HDD (USB 2.0, sadly). Both connections are slow (and my data is ~1TB), but I am confused how compression or careful diffing could speed things up if all this requires my CPU reading in the data in the first place, no? Both drives are local in this sense. (I cannot replace the SMB connection with SSH via rsync, as it cannot handle my password.) Or even with a remote drive, I am confused how rsync could do its magic if there is no one on the other end doing the compression before the data gets to the local CPU.
Is this a reasonable setup for such a copy?
rsync -vhcrC --progress src dest
-c: Maybe checksums are a bad idea, file size and timestamp might be the only thing rsync can check without loading the data in in the first place. -h: human-readable output -v: verbose -C: skipping what CVS skips
-a: I am not interested in archiving, as files move from Windows to mac, permissions will change anyway, I think -z: this is the compression issue -W: sometimes copying whole-files-only use less of the CPU, but some files are really big here (~100GB), and an interrupted transfer is better restarted