XNBD-CLIENT(1)						      General Commands Manual						    XNBD-CLIENT(1)

NAME

       xnbd-client -- connect to a server running xnbd-server(8), to use its exported block device

SYNOPSIS

       xnbd-client  [--blocksize  SIZE]   [--connect]	[--exportname  NAME]   [--recovery-command  COMMAND]   [--recovery-command-reboot COMMAND]
       [--retry COUNT]	[--timeout SECONDS] NBD-DEVICE	[      HOST	   PORT 	...]

       xnbd-client [bs=SIZE]  [timeout=SECONDS] HOST	   PORT NBD-DEVICE

       xnbd-client --disconnect NBD-DEVICE

       xnbd-client --check NBD-DEVICE

DESCRIPTION

       With xnbd-client, you can connect to a server running xnbd-server or xnbd-wrapper, thus using raw diskspace from that server as a  blockde-
       vice on the local client.

       To  do  this,  support from the Linux Kernel is necessary, in the form of the Network Block Device (NBD). When you have that, either in the
       kernel, or as a module, you can connect to an NBD server and use its exported file through a block special file with major mode 43.

       Long options can also be specified with two leading dashes. Some options are call compatible  to  nbd-client(1)	as  are  most  behavioural
       switches. This makes xnbd-client a plug-in replacement for nbd-client.

OPTIONS

       The following options are supported:

       --blocksize SIZE
		 Use  the provided value as block size.  Default is 1024; allowed values are either 512, 1024, 2048 or 4096.  For best results use
		 a block size value of 4096

		 For compatibility to nbd-client(1) you can also use bs=SIZE

       --check|-c
		 Check whether the specified nbd device is connected.

		 If the device is connected, xnbd-client will exit with an exit state of 0 and print the PID of the xnbd-client instance that con-
		 nected it to stdout.

		 If  the device is not connected or does not exist (for example because the nbd module was not loaded), xnbd-client will exit with
		 an exit state of 1 and not print anything on stdout.

		 If an error occurred, xnbd-client will exit with an exit state of 2, and not print anything on stdout either.

       --connect|-C
		 Connect to the nbd-server

       --disconnect|-d
		 Disconnect the specified nbd device from the server. Terminates execution with an exit state of 0 on success.

       --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 a xnbd-wrapper  and only succeeds, if the remote host is exporting the requested device.

       --retry COUNT
		 Try  up  to  "COUNT"  times  to  connect to the associated nbd-server. Default is 1, that is nbd-client will stop after the first
		 unsuccessful try.

       --recovery-command
		 invoke a specified command "COMMAND" on unexpected disconnection

       --recovery-command-reboot
		 Invoke the reboot(8) command on unexpected disconnection

       --timeout SECONDS
		 Use a timeout period (default is 0 which means not to use a timeout).	Please do not use this option for now, as it seems not	to
		 work due to a bug in the kernel module.

		 For compatibility to nbd-client(1) you can also use timeout=SECONDS

POSITIONAL ARGUMENTS

       The following positional options are supported:

       HOST	 The site to connect to a remote xnbd-server. You can specify any resolvable hostname, IPv4 or IPv6 address.

       PORT	 The port number to connect to on remote side

       NBD-DEVICE
		 The local nbd-device to be associated with the remote xnbd-server.

       You  can  specify  multiple host port	 tuples. xnbd-client will try to connect to each of them in order until it succeeds to establish a
       connection to a server.

BUGS

       The NBD device is known to deadlock when not being used altogether with the deadline scheduler. Make sure to do:

       echo deadline > /sys/block/nbd0/queue/scheduler

SEE ALSO

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

AUTHOR

       The NBD kernel module and the NBD tools have been written by  Pavel  Macheck  (pavel@ucw.cz)  and  is  now  maintained  by  Paul  Clements.
       (Paul.Clements@steeleye.com).

       The xNBD userland (client and server) have been written by Takahiro Hirofuchi (t.hirofuchi@aist.go.jp)

       This  manual page was written by Arno Toell (debian@toell.net) for the Debian GNU/Linux system (but may be used by others). Large parts are
       verbatim copies of the original nbd-server and nbd-client manual pages  written	by  Wouter  Verhelst  (wouter@debian.org).  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.

																    XNBD-CLIENT(1)