With NBD you can access block device on remote host just as it was in your
local /dev. It works with companion with the kernel nbd driver and consists
of a server and a client. Communication between client and server works over
TCP/IP networking, but to the client program this is hidden: it looks like
a regular local file access to a block device special file such as /dev/nd0.

NBD kernel driver location: Device Drivers -> Block devices -> Network block
device support The kernel driver needs only to be compiled on client side.