Download the Subsonic .deb package and install it:
Change user (i have set pi instead of root) :
For troubleshooting interesting files are here: /var/subsonic
It was interesting because it allowed me to understand why Subsonic web interface was OK but impossible to play a file :
It was a problem linked with ffmpeg. I think the problem comes from the fact that ffmpeg given in deb is made for ubuntu/debian but probably not ARM processor. THis is why I install ffmpeg from repository and then linked Subsonic folder to this ffmpeg freshly installed:
Configure Subsonic using web interface and admin account.
It worked! I could play my music from Astana, Kazakhstan while it was actually stocked in my Raspberry in Paris!
In my opinion it works quiet nice! Not laggy I mean.