I've been thinking about this quite a fair bit as my girlfriend has a Windows laptop and I have a MacBook Pro. We both have libraries on our devices and I want to find a way that we both share a central music library that we can take away with us. I have a file server on the local network and could use rsync, Windows sync or other such tools to keep the libraries up-to-date which is great for desktops but for devices that both roam and want to be able to access the library whilst roaming this won't work. I think BitTorrent Sync has a lot of promise for providing a solution for synchronising the music itself but I don't think any solution will work for the iTunes library. Here's the scenario: Laptop A and Desktop B initially sync their iTunes libraries together on the local network Laptop A goes roaming An album is deleted from Laptop A A CD is imported on Desktop B Laptop A rejoins the network Both devices sync together And this is what you will most likely see on both devices: The deleted album will be removed from the Music folder but will still exist in the library The CD will be on the file system and in the library on both devices This is because the iTunes library is a series of XML files so the file with the most recent modified timestamp will win. I'm going to carry out some testing though as iTunes keeps a separate XML file the library itself, deletions, additions, last played and last modified. In theory, if both of the devices have active network connections at the time things are changed (and the ports are open on the home network firewall) then changes shouldn't build up and everything may well be synced together nicely albeit have the potential to consume a lot of data. In reality though I think most changes (even playing a song counts as a change) would be made offline on the laptop and cause pretty big headaches when its time to sync up. It would be absolutely wonderful if iTunes had a built-in watch feature (the Automatically Add folder moves music out when added) that can keep an eye on the music folder and update the library automatically. Alas, the feature doesn't exist and someone has yet to write a nice piece of software that does the job well. In summary, I think it will useful for syncing the music itself between all of the devices but each library will need agreed human interaction to keep it happy. Sorry. No easy solution.
