There're the requirements/expectations:
- ability to both backup to an external drive and update local copy from an external HDD
- ability to produce non-compressed backup copy (the intention is to backup lots of images, those do not compress well anyway and it's time-consuming)
- ability to detect differences and backup/update only changed/added/removed files, not the whole archive
- ability to sync the folder structure as well
- capability to pre-setup desired backups so as to simplify the process of backing up the data (basically, ability to start the backup / local update in one click)
- user-friendliness. At least, after an initial configuration. End-user is not a computer-savvy person and not English-proficient either. So the software would preferably have icons and be generally easy to use
- (optional but preferred) free software
Essentially, there're 2 PCs with the same library of images and (separately) some documents. The intention is to keep a backup copy on a couple of external HDDs and, as changes may come from both PCs, use the HDDs to synchronise the library and documents among the PCs, while using the HDDs as a main backup.
So far I've tried several kinds of backup software and none was it. FBackup, for instance, failed to sync the same library from 2 PCs. Some other wouldn't produce non-compressed backup copies, another one could only backup the whole archive, not the changed files or could only backup files, but not the folder structure.
Thank you in advance.