I am looking for software suggestions for regularly generating off-computer discreete backups of large collections of music rapidly and accurately. I have ytaditionally maintained 3 independent 5 Tb hard drives backing up a collection of FLAC files and folders amounting to near 10,000 albums. I have been using Free File Sync, but this software is changing management rapidly and I fear that problems may exist with this in the near future.

What software do you use to keep and to protect Your Flac file music collections on remote hard drives?