Provided by: xnbd-server_0.3.0-3_amd64 bug


       xnbd-bgctl - Control a server running xnbd-server(8) through its control socket


       xnbd-bgctl --query CONTROL_SOCKET

       xnbd-bgctl [--force] --switch CONTROL_SOCKET

       xnbd-bgctl [--progress] --cache-all CONTROL_SOCKET

       xnbd-bgctl --cache-all2 CONTROL_SOCKET

       xnbd-bgctl [--exportname NAME] --reconnect CONTROL_SOCKET REMOTE_HOST REMOTE_PORT


       With the xnbd-bgctl command you can connect to an xnbd-server control channel and instruct
       it to act as directed. You may pass an argument to the control program which is then
       forwarded, on your behalf, to the server instance.


       The following options are supported:

           If the remote xnbd-server acts as proxy server, this command instructs the controlling
           xnbd-server instance to cache all blocks on its associated block disk. Upon completion
           the controlled xnbd-server instance holds all data from the origin instance and it is
           no longer necessary to act as proxy.

           This command is identical to --cache-all but detaches the process from the terminal
           and is hence using a dedicated connection for data transfer. Not implemented fully

           This command retrieves completion statistics from the proxy server instance. It
           returns the number of cached blocks on the server.

           This command recovers from a lost connection by re-establishing connectivity with the
           origin server. This command expects two additional arguments, the REMOTE_HOST, and the
           REMOTE_PORT you want to connect to, to recover from a disconnected session.

           This command stops the proxy server and restarts in target mode. All client sessions
           are preserved.

       --exportname NAME
           If the server supports to access devices by an identifier, use NAME to request access
           to a particular volume. This command is useful in combination with an xnbd-wrapper,
           not a plain xnbd-server.

           Enables display of a progress bar on stderr. Disabled by default.

           Ignore risks, use with care. Disabled by default.

           Deprecated alias to --switch, please do not use.


       The following positional options are supported:

           The Unix domain socket, the xnbd-server(8) program is listening on.


       xnbd-server(8), xnbd-wrapper(8), xnbd-wrapper-ctl(8)


       The NBD kernel module and the NBD tools have been written by Pavel Macheck (
       and is now maintained by Paul Clements (

       The xNBD userland programs have been written by Takahiro Hirofuchi

       This manual page was written by Arno Toell ( for the Debian GNU/Linux
       system (but may be used by others). Permission is granted to copy, distribute and/or
       modify this document under the terms of the GNU General Public License, version 2, as
       published by the Free Software Foundation.