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8 manpage.1: manpage.sgml
12 <!-- Fill in your name for FIRSTNAME and SURNAME. -->
13 <!ENTITY dhfirstname "<firstname>Wouter</firstname>">
14 <!ENTITY dhsurname "<surname>Verhelst</surname>">
15 <!-- Please adjust the date whenever revising the manpage. -->
16 <!ENTITY dhdate "<date>$Date$</date>">
17 <!-- SECTION should be 1-8, maybe w/ subsection other parameters are
18 allowed: see man(7), man(1). -->
19 <!ENTITY dhsection "<manvolnum>8</manvolnum>">
20 <!ENTITY dhemail "<email>wouter@debian.org</email>">
21 <!ENTITY dhusername "Wouter Verhelst">
22 <!ENTITY dhucpackage "<refentrytitle>NBD-CLIENT</refentrytitle>">
23 <!ENTITY dhpackage "nbd-client">
25 <!ENTITY debian "<productname>Debian GNU/Linux</productname>">
26 <!ENTITY gnu "<acronym>GNU</acronym>">
40 <holder>&dhusername;</holder>
50 <refname>&dhpackage;</refname>
52 <refpurpose>connect to a server running nbd-server(1), to use its
53 exported block device</refpurpose>
57 <command>&dhpackage;</command>
58 <arg><option>bs=<replaceable>blocksize</replaceable></option></arg>
59 <arg><option>timeout=<replaceable>seconds</replaceable></option></arg>
60 <arg choice=plain><option><replaceable>host</replaceable></option></arg>
61 <arg choice=plain><option><replaceable>port</replaceable></option></arg>
62 <arg choice=plain><option><replaceable>nbd-device</replaceable></option></arg>
63 <arg><option>-sdp</option></arg>
64 <arg><option>-swap</option></arg>
65 <arg><option>-persist</option></arg>
68 <command>&dhpackage;</command>
69 <arg choice=plain><option>-d <replaceable>nbd-device</replaceable></option></arg>
72 <command>&dhpackage;</command>
73 <arg choice="plain"><option>-c <replaceable>nbd-device</replaceable></option></arg>
77 <title>DESCRIPTION</title>
79 <para>With <command>&dhpackage;</command>, you can connect to a
80 server running <command>nbd-server</command>, thus using raw
81 diskspace from that server as a blockdevice on the local
84 <para>To do this, support from the Linux Kernel is necessary, in
85 the form of the Network Block Device (NBD). When you have that,
86 either in the kernel, or as a module, you can connect to an NBD
87 server and use its exported file through a block special file with
92 <title>OPTIONS</title>
94 <para>The following options are supported:</para>
98 <term><option>bs=<replaceable>blocksize</replaceable></option></term>
100 <para>Use a blocksize of "blocksize". Default is 1024;
101 allowed values are either 512, 1024, 2048 or 4096</para>
105 <term><option>host</option></term>
107 <para>The hostname of the machine running
108 <command>nbd-server</command>.</para>
112 <term><option>timeout=<replaceable>seconds</replaceable></option></term>
114 <para>Set the connection timeout to "seconds". For this to
115 work, you need a kernel with support for the NBD_SET_TIMEOUT
116 ioctl; this was introduced into Linus' tree on 2007-10-11,
117 and will be part of kernel 2.6.24.</para>
121 <term><option>port</option></term>
123 <para>The TCP port on which <command>nbd-server</command> is
124 running at the server.</para>
128 <term><option>nbd-device</option></term>
130 <para>The block special file this nbd-client should connect
137 <para>Check whether the specified nbd device is
139 <para>If the device is connected, &dhpackage; will exit
140 with an exit state of 0 and print the PID of the &dhpackage;
141 instance that connected it to stdout.
142 <para>If the device is not
143 connected or does not exist (for example because the nbd
144 module was not loaded), &dhpackage; will exit with an exit
145 state of 1 and not print anything on stdout.</para>
146 <para>If an error occurred, &dhpackage; will exit with an exit
147 state of 2, and not print anything on stdout either.</para>
153 <para>Disconnect the specified nbd device from the
158 <term>-persist</term>
160 <para>When this option is specified, &dhpackage; will
161 immediately try to reconnect an nbd device if the
162 connection ever drops unexpectedly due to a lost
163 server or something similar.</para>
167 <term><option>-sdp</option></term>
169 <para>Connect to the server using the Socket Direct Protocol
170 (SDP), rather than IP. See nbd-server(1) for details.
175 <term><option>-swap</option></term>
177 <para>Specifies that this NBD device will be used as
178 swapspace. If you intend to do that, please use this
179 option to prevent deadlocks. You'll need a special kernel
180 patch, available at NBD's homepage:
181 http://atrey.karlin.mff.cuni.cz/~pavel</para>
187 <title>EXAMPLES</title>
189 <para>Some examples of nbd-client usage:</para>
190 <itemizedlist mark="none">
192 <para>To connect to a server running on port 2000 at host
193 "server.domain.com", using the client's block special file
195 <para><command>nbd-client server.domain.com 2000
196 /dev/nb0</command></para>
199 <para>To connect to a server running on port 2001 at host
200 "swapserver.domain.com", using the client's block special
201 file "/dev/nb1", for swap purposes:</para>
202 <para><command>nbd-client swapserver.domain.com 2001 /dev/nb1
203 -swap</command></para>
206 <para>To disconnect the above connection again (after making
207 sure the block special file is not in use anymore):</para>
208 <para><command>nbd-client -d /dev/nb1</command></para>
213 <title>SEE ALSO</title>
215 <para>nbd-server (1).</para>
219 <title>AUTHOR</title>
220 <para>The NBD kernel module and the NBD tools have been written by
221 Pavel Macheck (pavel@ucw.cz).</para>
223 <para>The kernel module is now maintained by Paul Clements
224 (Paul.Clements@steeleye.com), while the userland tools are maintained by
225 Wouter Verhelst (wouter@debian.org)</para>
227 <para>This manual page was written by &dhusername; (&dhemail;) for
228 the &debian; system (but may be used by others). Permission is
229 granted to copy, distribute and/or modify this document under the
230 terms of the <acronym>GNU</acronym> General Public License,
231 version 2, as published by the Free Software Foundation.</para>
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