My primary flac storage is on Win2K on a RAID5 Volume. I tag my FLAC files with MP3tag and it all has been working fine. I recently bought a new external USB drive to be a backup to the RAID5 Volume and sync'd my files using rsync (available through cygwin)

It would incrementally sync my files between the primary volume and the secondary, but I've noticed after updating tags with mp3tag that the modification date/times aren't changing (it seems to preserve the datetime to the original timestamps).

This seems to confuse rsync and the files with the new tags aren't sync'd.

I guess that there is some extra padding in the flac files that the tags can change and not modify the file size of the FLACs, but if after editing the tags the timestamps don't change, than rsync won't notice and recopy the files.

I even used the --checksum option of rsync, that just seemed to take much, much longer and the changed files still weren't syncd.

How do other more experienced users sync their collections via rsync?

I can't offer any help specifically related to rsync, but MP3Tag can be set to modify the file time/date when the tags are updated - go under Options -> Tags and uncheck "Preserve file modification time when saving tags."

Yes, that fixed it, thanks. That is a must check if you are using MP3Tag and rsync to copy your flacs around.