Rsync is used for all copying to backup media.
Mirror new files on SSD to HDD.
karl@erlangen:~> time rsync -av /home/Albums/ /home-HDD/backup/home/Albums/ sending incremental file list sent 4,492,931 bytes received 11,148 bytes 3,002,719.33 bytes/sec total size is 185,751,103,178 speedup is 41,240.64 real 0m0,720s user 0m0,359s sys 0m0,360s karl@erlangen:~>
External disks are used for syncing machines. Specify '--delete' to avoid transfer of stale files.
karl@erlangen:~> time rsync -nav --delete /home/Albums/Bilder/ /run/media/karl/WD25/backup/home/Albums/Bilder/ sending incremental file list sent 1,448,755 bytes received 4,831 bytes 2,907,172.00 bytes/sec total size is 160,243,360,852 speedup is 110,240.03 (DRY RUN) real 0m0,369s user 0m0,138s sys 0m0,233s karl@erlangen:~>