How to sync KDE baloo/nepomuk indexes across machines?

Question

The KDE 4 file manager Dolphin allows to tag, rate, and comment files, if Nepomuk desktop search or its successor Baloo is enabled. All that tagging, rating, and commenting works fine on one computer, but looking at the same files on another computer doesn't show any of the filled in ratings etc. That's because that meta-information is stored in databases on the local computer. Is there any halfway straightforward way to sync Nepomuk/Baloo databases to other computers?

Answer 1

Since no one replied, I asked on the KDE forums. The short answer is that file attributes are stored in the file's extended attributes (xattr), not in some external database, and will therefore work regardless if Baloo or Nepomuk is enabled or disabled. The long answer, including a link to an interesting article that points out that xattr are supported across Linux, Mac OS X, and BSD, can be found here:

https://forum.kde.org/viewtopic.php?f=154&t=128875

Summary: If you use file systems that supports xattr (eg, ext4), and if you transfer between file systems with an application that preserves xattr (eg, rsync), your extended attributes (ratings, tags, comments, etc.) should be preserved.