If you’re running out of space on your Pi’s SD memory card or want to share folders under Linux, you should consider using the Linux network file system (NFS). All you need to do is to install rpcbind, nfs-common and nfs-kernel-server on your Pi.
On a freshly installed you must enable the rpcbind service before you can start the nfs-kernel-server:
$ sudo update-rc.d rpcbind enable
The network file system is particularly useful if you want to merge folders across your home network which reside on different systems. In order to listen to my ogg/mp3 music collection I’ve attached a Raspberry Pi to the AUX input of my Hi-Fi equipment. The collection resides on a USB stick and can be accessed with the music player daemon (mpd) and Minion, so that I can use my smartphone as a remote. Another music collection resides on my AVM Fritz Box, which acts as a mediaserver and NAS.