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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>
66 <arg><option>-nofork</option></arg>
69 <command>&dhpackage;</command>
70 <arg choice=plain><option>-d <replaceable>nbd-device</replaceable></option></arg>
73 <command>&dhpackage;</command>
74 <arg choice="plain"><option>-c <replaceable>nbd-device</replaceable></option></arg>
78 <title>DESCRIPTION</title>
80 <para>With <command>&dhpackage;</command>, you can connect to a
81 server running <command>nbd-server</command>, thus using raw
82 diskspace from that server as a blockdevice on the local
85 <para>To do this, support from the Linux Kernel is necessary, in
86 the form of the Network Block Device (NBD). When you have that,
87 either in the kernel, or as a module, you can connect to an NBD
88 server and use its exported file through a block special file with
93 <title>OPTIONS</title>
95 <para>The following options are supported:</para>
99 <term><option>bs=<replaceable>blocksize</replaceable></option></term>
101 <para>Use a blocksize of "blocksize". Default is 1024;
102 allowed values are either 512, 1024, 2048 or 4096</para>
106 <term><option>host</option></term>
108 <para>The hostname of the machine running
109 <command>nbd-server</command>.</para>
113 <term><option>timeout=<replaceable>seconds</replaceable></option></term>
115 <para>Set the connection timeout to "seconds". For this to
116 work, you need a kernel with support for the NBD_SET_TIMEOUT
117 ioctl; this was introduced into Linus' tree on 2007-10-11,
118 and will be part of kernel 2.6.24.</para>
122 <term><option>port</option></term>
124 <para>The TCP port on which <command>nbd-server</command> is
125 running at the server.</para>
129 <term><option>nbd-device</option></term>
131 <para>The block special file this nbd-client should connect
138 <para>Check whether the specified nbd device is
140 <para>If the device is connected, &dhpackage; will exit
141 with an exit state of 0 and print the PID of the &dhpackage;
142 instance that connected it to stdout.
143 <para>If the device is not
144 connected or does not exist (for example because the nbd
145 module was not loaded), &dhpackage; will exit with an exit
146 state of 1 and not print anything on stdout.</para>
147 <para>If an error occurred, &dhpackage; will exit with an exit
148 state of 2, and not print anything on stdout either.</para>
154 <para>Disconnect the specified nbd device from the
159 <term>-persist</term>
161 <para>When this option is specified, &dhpackage; will
162 immediately try to reconnect an nbd device if the
163 connection ever drops unexpectedly due to a lost
164 server or something similar.</para>
168 <term><option>-sdp</option></term>
170 <para>Connect to the server using the Socket Direct Protocol
171 (SDP), rather than IP. See nbd-server(1) for details.
176 <term><option>-swap</option></term>
178 <para>Specifies that this NBD device will be used as
179 swapspace. This option attempts to prevent deadlocks by
180 performing mlockall() at an appropriate time. It does not
181 however guarantee that such deadlocks can be avoided.</para>
185 <term><option>-nofork</option></term>
187 <para>Specifies that the NBD client should not detach and
188 daemonize itself. This is mostly useful for debugging.</para>
193 <title>EXAMPLES</title>
195 <para>Some examples of nbd-client usage:</para>
196 <itemizedlist mark="none">
198 <para>To connect to a server running on port 2000 at host
199 "server.domain.com", using the client's block special file
201 <para><command>nbd-client server.domain.com 2000
202 /dev/nb0</command></para>
205 <para>To connect to a server running on port 2001 at host
206 "swapserver.domain.com", using the client's block special
207 file "/dev/nb1", for swap purposes:</para>
208 <para><command>nbd-client swapserver.domain.com 2001 /dev/nb1
209 -swap</command></para>
212 <para>To disconnect the above connection again (after making
213 sure the block special file is not in use anymore):</para>
214 <para><command>nbd-client -d /dev/nb1</command></para>
219 <title>SEE ALSO</title>
221 <para>nbd-server (1).</para>
225 <title>AUTHOR</title>
226 <para>The NBD kernel module and the NBD tools have been written by
227 Pavel Macheck (pavel@ucw.cz).</para>
229 <para>The kernel module is now maintained by Paul Clements
230 (Paul.Clements@steeleye.com), while the userland tools are maintained by
231 Wouter Verhelst (wouter@debian.org)</para>
233 <para>This manual page was written by &dhusername; (&dhemail;) for
234 the &debian; system (but may be used by others). Permission is
235 granted to copy, distribute and/or modify this document under the
236 terms of the <acronym>GNU</acronym> General Public License,
237 version 2, as published by the Free Software Foundation.</para>
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