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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>september 19, 2001</date>">
17 <!-- SECTION should be 1-8, maybe w/ subsection other parameters are
18 allowed: see man(7), man(1). -->
19 <!ENTITY dhsection "<manvolnum>1</manvolnum>">
20 <!ENTITY dhemail "<email>wouter@debian.org</email>">
21 <!ENTITY dhusername "Wouter Verhelst">
22 <!ENTITY dhucpackage "<refentrytitle>NBD-SERVER</refentrytitle>">
23 <!ENTITY dhpackage "nbd-server">
25 <!ENTITY debian "<productname>Debian GNU/Linux</productname>">
26 <!ENTITY gnu "<acronym>GNU</acronym>">
40 <holder>&dhusername;</holder>
50 <refname>&dhpackage;</refname>
52 <refpurpose>serve a file as a block device to other computers
53 running the Linux(tm) Operating System</refpurpose>
57 <command>&dhpackage;</command>
59 <arg><option>-c <replaceable>this</replaceable></option></arg>
60 <arg choice=plain><replaceable>port</replaceable</arg>
61 <arg choice=plain><replaceable>filename</replaceable></arg>
62 <arg><replaceable>size</replaceable></arg>
63 <arg><option>-r</option></arg>
64 <arg><option>-m</option></arg>
65 <arg><option>-c</option></arg>
69 <title>DESCRIPTION</title>
71 <para>This manual page documents the
72 <command>&dhpackage;</command> command.</para>
74 <para>This manual page was written for the &debian; distribution
75 because the original program does not have a manual page.</para>
77 <para><command>&dhpackage;</command> is the server for the Linux
78 Network Block Device (NBD). With NBD, a client can use a file,
79 exported over the network from a server, as a block device. It can
80 then be used for whatever purpose a normal block device (harddisk,
81 CD-ROM, ...) can be used for.</para>
83 <para>NBD can be usefull for diskless clients that need swapspace,
84 but you can also create a filesystem on it and use it as though it
85 were a local filesystem.</para>
87 <para><command>&dhpackage;</command> implements some security
88 through a file called "nbd_server.allow" in the current directory.
89 This file must list the IP-addresses of clients that are allowed
90 to connect. If it does not exist, all clients are able to connect.
91 If the file is empty, no clients can connect.</para>
94 <title>OPTIONS</title>
98 <term><option>port</option>
101 <para>The port the server should listen to. A valid port is
102 any number between 1 and 65536; if 0 is used, nbd-server
103 will listen on stdin (so that nbd-server can be ran from
108 <term><option>filename</option></term>
110 <para>The filename of the file that should be exported. This
111 can be any file, including "real" blockdevices (i.e. a file
112 from /dev). If the filename includes the literal string
113 "%s", then this %s will be substituded with the IP-address
114 of the client trying to connect.</para>
118 <term><option>size</option></term>
120 <para>The size of the block device at the client side. This
121 is especially usefull in conjunction with the -m
123 <para>Can optionally be followed by one of K,k,M or
124 m, in which case the size will be multiplied by 1024 (K
125 or k) or 1048576 (M or m)</para>
129 <term><option>-r</option></term>
131 <para>Export the file read-only. If a client tries to write
132 to a read-only exported file, it will receive an error, but
133 the connection will stay up.</para>
137 <term><option>-m</option></term>
139 <para>Work with multiple files. This can be used to export
140 blockdevices that are larger than the maximum allowed
141 filesize on a given filesystem; i.e. when the filesystem
142 does not allow files larger than 2GB (which is true for
143 Linux 2.2 and below), you can use this option to store the
144 data in multiple files and export a larger filesystem, if
149 <term><option>-c</option></term>
151 <para>Copy on write. When this option is provided,
152 write-operations are not done to the exported file, but to a
153 separate file. This separate file is removed when the
154 connection is closed, which means that serving this way will
155 make nbd-server slow down (especially on large block devices
156 with lots of writes), and that after disconnecting and
157 reconnecting the client or the server, all changes are
164 <title>EXAMPLES</title>
165 <para>Some examples of nbd-server usage:</para>
166 <itemizedlist mark="none">
168 <para>To export a file /export/nbd/exp-bl-dev on port 2000:</para>
169 <para><command>nbd-server 2000 /export/nbd/exp-bl-dev</command></para>
172 <para>To export a the same file read-only:</para>
173 <para><command>nbd-server 2000 /export/nbd/exp-bl-dev -r</command></para>
176 <para>To export the same file read-write, but make sure
177 changes are lost after restarting the client or the
179 <para><command>nbd-server 2000 /export/nbd/exp-bl-dev
187 <para><filename>nbd_server.allow</filename></para>
191 <title>SEE ALSO</title>
193 <para>nbd-client (8).</para>
197 <title>AUTHOR</title>
199 <para>This manual page was written by &dhusername; (&dhemail;) for
200 the &debian; system (but may be used by others). Permission is
201 granted to copy, distribute and/or modify this document under
202 the terms of the <acronym>GNU</acronym> Free Documentation
203 License, Version 1.1 or any later version published by the Free
204 Software Foundation; with no Invariant Sections, no Front-Cover
205 Texts and no Back-Cover Texts.</para>
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