network block device

The Network Block Device (NBD) is a protocol, originally implemented for Linux but that now has a number of implementations that lets a computer access a remote storage device (like a hard drive or partition) as if it were a local, physical disk, using a simple client-server model over a TCP/IP network. This allows remote booting, swapping, or filesystem access without complex network file systems like NFS. It works by exporting a block device from a server and presenting it as a local block device on a client machine, allowing standard block-level operations (read/write) over the network. To install the package, download the source and do the normal configure / make / make install dance. You'll need to install it on both the client and the server. NBD is quite easy to use. First, on the client, you need to load the module and, if you're not using udev, to create the device nodes: (if you need more than one NBD device, repeat the above command for nbd1, nbd2, ...) Next, write a configuration file for the server. An example looks like this: Note that the filename must be an absolute path; i.e., something like /path/to/file , not ../file . See the nbd-server manpage for details on any available options. nbd-client must be ran as root; the same is not true for nbd-server (but do make sure that /var/run is writeable by the server that nbd-server runs as; otherwise, you won't get a PID file, though the server will keep running). There are packages (or similar) available for most current operating systems; see the "Packaging status" badge below for details. Besides this project, the NBD protocol has been implemented by various other people. A (probably incomplete) list follows: nbdkit is a multithreaded NBD server with a plugin architecture. libnbd is a library to aid in writing NBD clients qemu contains an embedded NBD server, an embedded NBD client, and a standalone NBD server ( qemu-nbd ). They maintain a status document of their NBD implementation. A GEOM gate-based client implementation for FreeBSD exists. It has not seen any updates since 2018, and only implements the client side (any server should run on FreeBSD unmodified, however). A Windows client implementation exists as part of the RBD implementation of Ceph for Windows. lwNBD is a NBD server library, targetting bare metal or OS embedded system. It has a plugin architecture. xnbd: This was an NBD implementation with a few extra protocol messages that allowed for live migration. Its code repository has disappeared. enbd: This was an NBD implementation with a few extra protocol messages that allowed extra ioctl calls to be passed on (e.g., the "eject" message for a CD-ROM device that was being exported through NBD). It appears to no longer be maintained. Hurd translator: There was a proof-of-concept implementation of the NBD protocol once as a translator for The Hurd. We do not know what its current status is. Christoph Lohmann once wrote a client implementation for Plan 9. The link he provided us is now stale; we do not know what its current status is.