xnbd-bgctl(1) 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 yet.


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.


The NBD kernel module and the NBD tools have been written by Pavel Macheck ([email protected]) and is now maintained by Paul Clements ([email protected]).

The xNBD userland programs have been written by Takahiro Hirofuchi ([email protected]).

This manual page was written by Arno Toell ([email protected]) 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.