1: <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook V4.1//EN">
2: <book id="rsync">
3: <bookinfo>
4: <title>rsync</title>
5: <copyright>
6: <year>1996 -- 2002</year>
7: <holder>Martin Pool</holder>
8: <holder>Andrew Tridgell</holder>
9: </copyright>
10: <author>
11: <firstname>Martin</firstname>
12: <surname>Pool</surname>
13: </author>
14: </bookinfo>
15:
16: <chapter>
17: <title>Introduction</title>
18:
19: <para>rsync is a flexible program for efficiently copying files or
20: directory trees.
21:
22: <para>rsync has many options to select which files will be copied
23: and how they are to be transferred. It may be used as an
24: alternative to ftp, http, scp or rcp.
25:
26: <para>The rsync remote-update protocol allows rsync to transfer just
27: the differences between two sets of files across the network link,
28: using an efficient checksum-search algorithm described in the
29: technical report that accompanies this package.</para>
30:
31: <para>Some of the additional features of rsync are:</para>
32:
33: <itemizedlist>
34:
35: <listitem>
36: <para>support for copying links, devices, owners, groups and
37: permissions
38: </para>
39: </listitem>
40:
41: <listitem>
42: <para>
43: exclude and exclude-from options similar to GNU tar
44: </para>
45: </listitem>
46:
47: <listitem>
48: <para>
49: a CVS exclude mode for ignoring the same files that CVS would ignore
50: </listitem>
51:
52: <listitem>
53: <para>
54: can use any transparent remote shell, including rsh or ssh
55: </listitem>
56:
57: <listitem>
58: <para>
59: does not require root privileges
60: </listitem>
61:
62: <listitem>
63: <para>
64: pipelining of file transfers to minimize latency costs
65: </listitem>
66:
67: <listitem>
68: <para>
69: support for anonymous or authenticated rsync servers (ideal for
70: mirroring)
71: </para>
72: </listitem>
73: </itemizedlist>
74: </chapter>
75:
76:
77:
78: <chapter>
79: <title>Using rsync</title>
80: <section>
81: <title>
82: Introductory example
83: </title>
84:
85: <para>
86: Probably the most common case of rsync usage is to copy files
87: to or from a remote machine using
88: <application>ssh</application> as a network transport. In
89: this situation rsync is a good alternative to
90: <application>scp</application>.
91: </para>
92:
93: <para>
94: The most commonly used arguments for rsync are
95: </para>
96:
97: <variablelist>
98: <varlistentry>
99: <term><option>-v</option></term>
100: <listitem>
101: <para>Be verbose. Primarily, display the name of each file as it is copied.</para>
102: </listitem>
103: </varlistentry>
104:
105:
106: <varlistentry>
107: <term><option>-a</option></term>
108: <listitem>
109: <para>
110: Reproduce the structure and attributes of the origin files as exactly
111: as possible: this includes copying subdirectories, symlinks, special
112: files, ownership and permissions. (@xref{Attributes to
113: copy}.)
114: </para>
115: </listitem>
116: </varlistentry>
117: </variablelist>
118:
119:
120:
121: <para><option>-v </option>
122:
123: <para><option>-z</option>
124: Compress network traffic, using a modified version of the
125: @command{zlib} library.</para>
126:
127: <para><option>-P</option>
128: Display a progress indicator while files are transferred. This should
129: normally be omitted if rsync is not run on a terminal.
130: </para>
131: </section>
132:
133:
134:
135:
136: <section>
137: <title>Local and remote</title>
138:
139: <para>There are six different ways of using rsync. They
140: are:</para>
141:
142:
143:
144: <!-- one of (CALLOUTLIST GLOSSLIST ITEMIZEDLIST ORDEREDLIST SEGMENTEDLIST SIMPLELIST VARIABLELIST CAUTION IMPORTANT NOTE TIP WARNING LITERALLAYOUT PROGRAMLISTING PROGRAMLISTINGCO SCREEN SCREENCO SCREENSHOT SYNOPSIS CMDSYNOPSIS FUNCSYNOPSIS CLASSSYNOPSIS FIELDSYNOPSIS CONSTRUCTORSYNOPSIS DESTRUCTORSYNOPSIS METHODSYNOPSIS FORMALPARA PARA SIMPARA ADDRESS BLOCKQUOTE GRAPHIC GRAPHICCO MEDIAOBJECT MEDIAOBJECTCO INFORMALEQUATION INFORMALEXAMPLE INFORMALFIGURE INFORMALTABLE EQUATION EXAMPLE FIGURE TABLE MSGSET PROCEDURE SIDEBAR QANDASET ANCHOR BRIDGEHEAD REMARK HIGHLIGHTS ABSTRACT AUTHORBLURB EPIGRAPH INDEXTERM REFENTRY SECTION) -->
145: <orderedlist>
146: <listitem>
147: <para>
148: for copying local files. This is invoked when neither
149: source nor destination path contains a @code{:} separator
150:
151: <listitem>
152: <para>
153: for copying from the local machine to a remote machine using
154: a remote shell program as the transport (such as rsh or
155: ssh). This is invoked when the destination path contains a
156: single @code{:} separator.
157:
158: <listitem>
159: <para>
160: for copying from a remote machine to the local machine
161: using a remote shell program. This is invoked when the source
162: contains a @code{:} separator.
163:
164: <listitem>
165: <para>
166: for copying from a remote rsync server to the local
167: machine. This is invoked when the source path contains a @code{::}
168: separator or a @code{rsync://} URL.
169:
170: <listitem>
171: <para>
172: for copying from the local machine to a remote rsync
173: server. This is invoked when the destination path contains a @code{::}
174: separator.
175:
176: <listitem>
177: <para>
178: for listing files on a remote machine. This is done the
179: same way as rsync transfers except that you leave off the
180: local destination.
181:
182: </listitem>
183: </orderedlist>
184: <para>
185: Note that in all cases (other than listing) at least one of the source
186: and destination paths must be local.
187:
188: <para>
189: Any one invocation of rsync makes a copy in a single direction. rsync
190: currently has no equivalent of @command{ftp}'s interactive mode.
191:
192: @cindex @sc{nfs}
193: @cindex network filesystems
194: @cindex remote filesystems
195:
196: <para>
197: rsync's network protocol is generally faster at copying files than
198: network filesystems such as @sc{nfs} or @sc{cifs}. It is better to
199: run rsync on the file server either as a daemon or over ssh than
200: running rsync giving the network directory.
201: </para>
202: </section>
203: </chapter>
204:
205:
206:
207: <chapter>
208: <title>Frequently asked questions</title>
209:
210:
211: <!-- one of (CALLOUTLIST GLOSSLIST ITEMIZEDLIST ORDEREDLIST SEGMENTEDLIST SIMPLELIST VARIABLELIST CAUTION IMPORTANT NOTE TIP WARNING LITERALLAYOUT PROGRAMLISTING PROGRAMLISTINGCO SCREEN SCREENCO SCREENSHOT SYNOPSIS CMDSYNOPSIS FUNCSYNOPSIS CLASSSYNOPSIS FIELDSYNOPSIS CONSTRUCTORSYNOPSIS DESTRUCTORSYNOPSIS METHODSYNOPSIS FORMALPARA PARA SIMPARA ADDRESS BLOCKQUOTE GRAPHIC GRAPHICCO MEDIAOBJECT MEDIAOBJECTCO INFORMALEQUATION INFORMALEXAMPLE INFORMALFIGURE INFORMALTABLE EQUATION EXAMPLE FIGURE TABLE MSGSET PROCEDURE SIDEBAR QANDASET ANCHOR BRIDGEHEAD REMARK HIGHLIGHTS ABSTRACT AUTHORBLURB EPIGRAPH INDEXTERM SECTION SIMPLESECT REFENTRY SECT1) -->
212: <qandaset>
213: <!-- one of (QANDADIV QANDAENTRY) -->
214:
215: <qandaentry>
216: <question>
217: <!-- one of (CALLOUTLIST GLOSSLIST ITEMIZEDLIST ORDEREDLIST
218: SEGMENTEDLIST SIMPLELIST VARIABLELIST CAUTION IMPORTANT NOTE
219: TIP WARNING LITERALLAYOUT PROGRAMLISTING PROGRAMLISTINGCO
220: SCREEN SCREENCO SCREENSHOT SYNOPSIS CMDSYNOPSIS FUNCSYNOPSIS
221: CLASSSYNOPSIS FIELDSYNOPSIS CONSTRUCTORSYNOPSIS
222: DESTRUCTORSYNOPSIS METHODSYNOPSIS FORMALPARA PARA SIMPARA
223: ADDRESS BLOCKQUOTE GRAPHIC GRAPHICCO MEDIAOBJECT
224: MEDIAOBJECTCO INFORMALEQUATION INFORMALEXAMPLE
225: INFORMALFIGURE INFORMALTABLE EQUATION EXAMPLE FIGURE TABLE
226: PROCEDURE ANCHOR BRIDGEHEAD REMARK HIGHLIGHTS INDEXTERM) -->
227: <para>Are there mailing lists for rsync?
228: </question>
229:
230: <answer>
231: <para>Yes, and you can subscribe and unsubscribe through a
232: web interface at
233: <ulink
234: url="http://lists.samba.org/">http://lists.samba.org/</ulink>
235: </para>
236:
237: <para>
238: If you are having trouble with the mailing list, please
239: send mail to the administrator
240:
241: <email>rsync-admin@lists.samba.org</email>
242:
243: not to the list itself.
244: </para>
245:
246: <para>
247: The mailing list archives are searchable. Use
248: <ulink url="http://google.com/">Google</ulink> and prepend
249: the search with <userinput>site:lists.samba.org
250: rsync</userinput>, plus relevant keywords.
251: </para>
252: </answer>
253: </qandaentry>
254:
255:
256: <qandaentry>
257: <question>
258: <para>
259: Why is rsync so much bigger when I build it with
260: <command>gcc</command>?
261: </para>
262: </question>
263: <answer>
264: <para>
265: On gcc, rsync builds by default with debug symbols
266: included. If you strip both executables, they should end
267: up about the same size. (Use <command>make
268: install-strip</command>.)
269: </para>
270: </answer>
271: </qandaentry>
272:
273:
274: <qandaentry>
275: <question>
276: <para>Is rsync useful for a single large file like an ISO image?</para>
277: </question>
278: <answer>
279: <para>
280: Yes, but note the following:
281:
282: <para>
283: Background: A common use of rsync is to update a file (or set of files) in one location from a more
284: correct or up-to-date copy in another location, taking advantage of portions of the files that are
285: identical to speed up the process. (Note that rsync will transfer a file in its entirety if no copy
286: exists at the destination.)
287:
288: <para>
289: (This discussion is written in terms of updating a local copy of a file from a correct file in a
290: remote location, although rsync can work in either direction.)
291:
292: <para>
293: The file to be updated (the local file) must be in a destination directory that has enough space for
294: two copies of the file. (In addition, keep an extra copy of the file to be updated in a different
295: location for safety -- see the discussion (below) about rsync's behavior when the rsync process is
296: interrupted before completion.)
297:
298: <para>
299: The local file must have the same name as the remote file being sync'd to (I think?). If you are
300: trying to upgrade an iso from, for example, beta1 to beta2, rename the local file to the same name
301: as the beta2 file. *(This is a useful thing to do -- only the changed portions will be
302: transmitted.)*
303:
304: <para>
305: The extra copy of the local file kept in a different location is because of rsync's behavior if
306: interrupted before completion:
307:
308: <para>
309: * If you specify the --partial option and rsync is interrupted, rsync will save the partially
310: rsync'd file and throw away the original local copy. (The partially rsync'd file is correct but
311: truncated.) If rsync is restarted, it will not have a local copy of the file to check for duplicate
312: blocks beyond the section of the file that has already been rsync'd, thus the remainder of the rsync
313: process will be a "pure transfer" of the file rather than taking advantage of the rsync algorithm.
314:
315: <para>
316: * If you don't specify the --partial option and rsync is interrupted, rsync will throw away the
317: partially rsync'd file, and, when rsync is restarted starts the rsync process over from the
318: beginning.
319:
320: <para>
321: Which of these is most desirable depends on the degree of commonality between the local and remote
322: copies of the file *and how much progress was made before the interruption*.
323:
324: <para>
325: The ideal approach after an interruption would be to create a new file by taking the original file
326: and deleting a portion equal in size to the portion already rsync'd and then appending *the
327: remaining* portion to the portion of the file that has already been rsync'd. (There has been some
328: discussion about creating an option to do this automatically.)
329:
330: The --compare-dest option is useful when transferring multiple files, but is of no benefit in
331: transferring a single file. (AFAIK)
332:
333: *Other potentially useful information can be found at:
334: -[3]http://twiki.org/cgi-bin/view/Wikilearn/RsyncingALargeFile
335:
336: This answer, formatted with "real" bullets, can be found at:
337: -[4]http://twiki.org/cgi-bin/view/Wikilearn/RsyncingALargeFileFAQ*
338:
339: </para>
340: </answer>
341: </qandaentry>
342: </qandaset>
343: </chapter>
344:
345:
346: <appendix>
347: <title>Other Resources</title>
348:
349: <para><ulink url="http://www.ccp14.ac.uk/ccp14admin/rsync/"></ulink></para>
350: </appendix>
351: </book>
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