For further information on the client see the nbd client home page, where you also can find a nbdd server equivalent, running in user space. The nbdd server provides functionality similar to that of commercial UNIX implementation for distributing access to disks, like VSDs on AIX and CVM in Solaris.
Bug reports are welcome.
It is a patched version of Pavel's nbd client. All actions performed to configure the kernel is done as root. Note the the patch should work with later kernels as well. Reboot the new kernel and you are ready to go. Nbdd configuration example Nbdd device and module loading Load the nbdd server module, on the server machine.