Backup forum

So, my linux distro (opensuse) has been working with crashplan for years, but with the most recent update a few days ago, it no longer works.  I found some possible leads, but it seems like it's time to switch, and initial research says that IDrive may be just what I want.  The thing that excited me the most was the IDrive Express.  I have 3+ TB of disk I want to backup via cable modem, and upload speeds being what they are, that'll be 3 months or more just to do the initial backup.

As I understand it, I can order an IDrive Express (even at the IDrive Personal level, I can do that 1/year for free) and they'll send me a disk.  I copy my files there, send it in, and after it's loaded in, I start backing up.  That is so exciting.  Am I understanding that correctly?

My only question is that it says that to put the files on the Express drive, use the IDrive app, but that only exists for mac/windows hosts.  Backing up to IDrive on linux is done using scripts.  Is there any issue with copying files to the Express drive using standard linux command line tools (such as rsync or cp) and having them correctly recognized so that once I start backing things up, it doesn't try to overwrite all the files I put on the Express drive?

If anyone has any experience doing an initial Express drive backup of a linux filesystem, I'd love to hear their experience.

Thanks in advance