lsyncdの制限

Be aware that the kernel limits the number of watches. You can see the limit 
in  
      /proc/sys/fs/inotify/max_user_watches

which is usually set to 8192. This means lsyncd cannot watch more than 8192
directories unless you change the kernel setting. Lsyncd itself has no
limits.

なんだって。
なのでsysctl.confに

fs.inotify.max_user_watches = 65536

を書いて

sudo sysctl -p