2008-09-03 15:38:45 +04:00
|
|
|
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
|
|
|
|
|
"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
|
|
|
|
|
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
|
|
|
|
|
<head>
|
|
|
|
|
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
|
2008-12-05 16:44:33 +03:00
|
|
|
<meta name="generator" content="AsciiDoc 8.2.7" />
|
2008-09-03 15:38:45 +04:00
|
|
|
<style type="text/css">
|
|
|
|
|
/* Debug borders */
|
|
|
|
|
p, li, dt, dd, div, pre, h1, h2, h3, h4, h5, h6 {
|
|
|
|
|
/*
|
|
|
|
|
border: 1px solid red;
|
|
|
|
|
*/
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
body {
|
|
|
|
|
margin: 1em 5% 1em 5%;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
a {
|
|
|
|
|
color: blue;
|
|
|
|
|
text-decoration: underline;
|
|
|
|
|
}
|
|
|
|
|
a:visited {
|
|
|
|
|
color: fuchsia;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
em {
|
|
|
|
|
font-style: italic;
|
2008-12-05 16:44:33 +03:00
|
|
|
color: navy;
|
2008-09-03 15:38:45 +04:00
|
|
|
}
|
|
|
|
|
|
|
|
|
|
strong {
|
|
|
|
|
font-weight: bold;
|
2008-12-05 16:44:33 +03:00
|
|
|
color: #083194;
|
2008-09-03 15:38:45 +04:00
|
|
|
}
|
|
|
|
|
|
|
|
|
|
tt {
|
|
|
|
|
color: navy;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
h1, h2, h3, h4, h5, h6 {
|
|
|
|
|
color: #527bbd;
|
|
|
|
|
font-family: sans-serif;
|
|
|
|
|
margin-top: 1.2em;
|
|
|
|
|
margin-bottom: 0.5em;
|
|
|
|
|
line-height: 1.3;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
h1, h2, h3 {
|
|
|
|
|
border-bottom: 2px solid silver;
|
|
|
|
|
}
|
|
|
|
|
h2 {
|
|
|
|
|
padding-top: 0.5em;
|
|
|
|
|
}
|
|
|
|
|
h3 {
|
|
|
|
|
float: left;
|
|
|
|
|
}
|
|
|
|
|
h3 + * {
|
|
|
|
|
clear: left;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
div.sectionbody {
|
|
|
|
|
font-family: serif;
|
|
|
|
|
margin-left: 0;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
hr {
|
|
|
|
|
border: 1px solid silver;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
p {
|
|
|
|
|
margin-top: 0.5em;
|
|
|
|
|
margin-bottom: 0.5em;
|
|
|
|
|
}
|
|
|
|
|
|
2008-12-05 16:44:33 +03:00
|
|
|
ul, ol, li > p {
|
|
|
|
|
margin-top: 0;
|
|
|
|
|
}
|
|
|
|
|
|
2008-09-03 15:38:45 +04:00
|
|
|
pre {
|
|
|
|
|
padding: 0;
|
|
|
|
|
margin: 0;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
span#author {
|
|
|
|
|
color: #527bbd;
|
|
|
|
|
font-family: sans-serif;
|
|
|
|
|
font-weight: bold;
|
|
|
|
|
font-size: 1.1em;
|
|
|
|
|
}
|
|
|
|
|
span#email {
|
|
|
|
|
}
|
|
|
|
|
span#revision {
|
|
|
|
|
font-family: sans-serif;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
div#footer {
|
|
|
|
|
font-family: sans-serif;
|
|
|
|
|
font-size: small;
|
|
|
|
|
border-top: 2px solid silver;
|
|
|
|
|
padding-top: 0.5em;
|
|
|
|
|
margin-top: 4.0em;
|
|
|
|
|
}
|
|
|
|
|
div#footer-text {
|
|
|
|
|
float: left;
|
|
|
|
|
padding-bottom: 0.5em;
|
|
|
|
|
}
|
|
|
|
|
div#footer-badges {
|
|
|
|
|
float: right;
|
|
|
|
|
padding-bottom: 0.5em;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
div#preamble,
|
|
|
|
|
div.tableblock, div.imageblock, div.exampleblock, div.verseblock,
|
|
|
|
|
div.quoteblock, div.literalblock, div.listingblock, div.sidebarblock,
|
|
|
|
|
div.admonitionblock {
|
|
|
|
|
margin-right: 10%;
|
|
|
|
|
margin-top: 1.5em;
|
|
|
|
|
margin-bottom: 1.5em;
|
|
|
|
|
}
|
|
|
|
|
div.admonitionblock {
|
|
|
|
|
margin-top: 2.5em;
|
|
|
|
|
margin-bottom: 2.5em;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
div.content { /* Block element content. */
|
|
|
|
|
padding: 0;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/* Block element titles. */
|
|
|
|
|
div.title, caption.title {
|
2008-12-05 16:44:33 +03:00
|
|
|
color: #527bbd;
|
2008-09-03 15:38:45 +04:00
|
|
|
font-family: sans-serif;
|
|
|
|
|
font-weight: bold;
|
|
|
|
|
text-align: left;
|
|
|
|
|
margin-top: 1.0em;
|
|
|
|
|
margin-bottom: 0.5em;
|
|
|
|
|
}
|
|
|
|
|
div.title + * {
|
|
|
|
|
margin-top: 0;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
td div.title:first-child {
|
|
|
|
|
margin-top: 0.0em;
|
|
|
|
|
}
|
|
|
|
|
div.content div.title:first-child {
|
|
|
|
|
margin-top: 0.0em;
|
|
|
|
|
}
|
|
|
|
|
div.content + div.title {
|
|
|
|
|
margin-top: 0.0em;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
div.sidebarblock > div.content {
|
|
|
|
|
background: #ffffee;
|
|
|
|
|
border: 1px solid silver;
|
|
|
|
|
padding: 0.5em;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
div.listingblock {
|
|
|
|
|
margin-right: 0%;
|
|
|
|
|
}
|
|
|
|
|
div.listingblock > div.content {
|
|
|
|
|
border: 1px solid silver;
|
|
|
|
|
background: #f4f4f4;
|
|
|
|
|
padding: 0.5em;
|
|
|
|
|
}
|
|
|
|
|
|
2008-12-05 16:44:33 +03:00
|
|
|
div.quoteblock {
|
2008-09-03 15:38:45 +04:00
|
|
|
padding-left: 2.0em;
|
|
|
|
|
}
|
2008-12-05 16:44:33 +03:00
|
|
|
div.quoteblock > div.attribution {
|
|
|
|
|
padding-top: 0.5em;
|
2008-09-03 15:38:45 +04:00
|
|
|
text-align: right;
|
|
|
|
|
}
|
2008-12-05 16:44:33 +03:00
|
|
|
|
|
|
|
|
div.verseblock {
|
|
|
|
|
padding-left: 2.0em;
|
|
|
|
|
}
|
|
|
|
|
div.verseblock > div.content {
|
|
|
|
|
white-space: pre;
|
|
|
|
|
}
|
|
|
|
|
div.verseblock > div.attribution {
|
|
|
|
|
padding-top: 0.75em;
|
|
|
|
|
text-align: left;
|
|
|
|
|
}
|
|
|
|
|
/* DEPRECATED: Pre version 8.2.7 verse style literal block. */
|
2008-09-03 15:38:45 +04:00
|
|
|
div.verseblock + div.attribution {
|
|
|
|
|
text-align: left;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
div.admonitionblock .icon {
|
|
|
|
|
vertical-align: top;
|
|
|
|
|
font-size: 1.1em;
|
|
|
|
|
font-weight: bold;
|
|
|
|
|
text-decoration: underline;
|
|
|
|
|
color: #527bbd;
|
|
|
|
|
padding-right: 0.5em;
|
|
|
|
|
}
|
|
|
|
|
div.admonitionblock td.content {
|
|
|
|
|
padding-left: 0.5em;
|
|
|
|
|
border-left: 2px solid silver;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
div.exampleblock > div.content {
|
|
|
|
|
border-left: 2px solid silver;
|
|
|
|
|
padding: 0.5em;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
div.imageblock div.content { padding-left: 0; }
|
|
|
|
|
div.imageblock img { border: 1px solid silver; }
|
|
|
|
|
span.image img { border-style: none; }
|
|
|
|
|
|
|
|
|
|
dl {
|
|
|
|
|
margin-top: 0.8em;
|
|
|
|
|
margin-bottom: 0.8em;
|
|
|
|
|
}
|
|
|
|
|
dt {
|
|
|
|
|
margin-top: 0.5em;
|
|
|
|
|
margin-bottom: 0;
|
2008-12-05 16:44:33 +03:00
|
|
|
font-style: normal;
|
2008-09-03 15:38:45 +04:00
|
|
|
}
|
|
|
|
|
dd > *:first-child {
|
2008-12-05 16:44:33 +03:00
|
|
|
margin-top: 0.1em;
|
2008-09-03 15:38:45 +04:00
|
|
|
}
|
|
|
|
|
|
|
|
|
|
ul, ol {
|
|
|
|
|
list-style-position: outside;
|
|
|
|
|
}
|
2008-12-05 16:44:33 +03:00
|
|
|
div.olist > ol {
|
|
|
|
|
list-style-type: decimal;
|
|
|
|
|
}
|
|
|
|
|
div.olist2 > ol {
|
2008-09-03 15:38:45 +04:00
|
|
|
list-style-type: lower-alpha;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
div.tableblock > table {
|
|
|
|
|
border: 3px solid #527bbd;
|
|
|
|
|
}
|
|
|
|
|
thead {
|
|
|
|
|
font-family: sans-serif;
|
|
|
|
|
font-weight: bold;
|
|
|
|
|
}
|
|
|
|
|
tfoot {
|
|
|
|
|
font-weight: bold;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
div.hlist {
|
|
|
|
|
margin-top: 0.8em;
|
|
|
|
|
margin-bottom: 0.8em;
|
|
|
|
|
}
|
|
|
|
|
div.hlist td {
|
2008-12-05 16:44:33 +03:00
|
|
|
padding-bottom: 15px;
|
2008-09-03 15:38:45 +04:00
|
|
|
}
|
|
|
|
|
td.hlist1 {
|
|
|
|
|
vertical-align: top;
|
2008-12-05 16:44:33 +03:00
|
|
|
font-style: normal;
|
2008-09-03 15:38:45 +04:00
|
|
|
padding-right: 0.8em;
|
|
|
|
|
}
|
|
|
|
|
td.hlist2 {
|
|
|
|
|
vertical-align: top;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
@media print {
|
|
|
|
|
div#footer-badges { display: none; }
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
div#toctitle {
|
|
|
|
|
color: #527bbd;
|
|
|
|
|
font-family: sans-serif;
|
|
|
|
|
font-size: 1.1em;
|
|
|
|
|
font-weight: bold;
|
|
|
|
|
margin-top: 1.0em;
|
|
|
|
|
margin-bottom: 0.1em;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
div.toclevel1, div.toclevel2, div.toclevel3, div.toclevel4 {
|
|
|
|
|
margin-top: 0;
|
|
|
|
|
margin-bottom: 0;
|
|
|
|
|
}
|
|
|
|
|
div.toclevel2 {
|
|
|
|
|
margin-left: 2em;
|
|
|
|
|
font-size: 0.9em;
|
|
|
|
|
}
|
|
|
|
|
div.toclevel3 {
|
|
|
|
|
margin-left: 4em;
|
|
|
|
|
font-size: 0.9em;
|
|
|
|
|
}
|
|
|
|
|
div.toclevel4 {
|
|
|
|
|
margin-left: 6em;
|
|
|
|
|
font-size: 0.9em;
|
|
|
|
|
}
|
|
|
|
|
/* Workarounds for IE6's broken and incomplete CSS2. */
|
|
|
|
|
|
|
|
|
|
div.sidebar-content {
|
|
|
|
|
background: #ffffee;
|
|
|
|
|
border: 1px solid silver;
|
|
|
|
|
padding: 0.5em;
|
|
|
|
|
}
|
|
|
|
|
div.sidebar-title, div.image-title {
|
2008-12-05 16:44:33 +03:00
|
|
|
color: #527bbd;
|
2008-09-03 15:38:45 +04:00
|
|
|
font-family: sans-serif;
|
|
|
|
|
font-weight: bold;
|
|
|
|
|
margin-top: 0.0em;
|
|
|
|
|
margin-bottom: 0.5em;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
div.listingblock div.content {
|
|
|
|
|
border: 1px solid silver;
|
|
|
|
|
background: #f4f4f4;
|
|
|
|
|
padding: 0.5em;
|
|
|
|
|
}
|
|
|
|
|
|
2008-12-05 16:44:33 +03:00
|
|
|
div.quoteblock-attribution {
|
|
|
|
|
padding-top: 0.5em;
|
|
|
|
|
text-align: right;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
div.verseblock-content {
|
|
|
|
|
white-space: pre;
|
|
|
|
|
}
|
|
|
|
|
div.verseblock-attribution {
|
|
|
|
|
padding-top: 0.75em;
|
|
|
|
|
text-align: left;
|
2008-09-03 15:38:45 +04:00
|
|
|
}
|
|
|
|
|
|
|
|
|
|
div.exampleblock-content {
|
|
|
|
|
border-left: 2px solid silver;
|
|
|
|
|
padding-left: 0.5em;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/* IE6 sets dynamically generated links as visited. */
|
|
|
|
|
div#toc a:visited { color: blue; }
|
2008-12-05 16:44:33 +03:00
|
|
|
|
|
|
|
|
/* Because IE6 child selector is broken. */
|
|
|
|
|
div.olist2 ol {
|
|
|
|
|
list-style-type: lower-alpha;
|
|
|
|
|
}
|
|
|
|
|
div.olist2 div.olist ol {
|
|
|
|
|
list-style-type: decimal;
|
|
|
|
|
}
|
2008-09-03 15:38:45 +04:00
|
|
|
</style>
|
|
|
|
|
<script type="text/javascript">
|
|
|
|
|
/*<+'])');
|
|
|
|
|
// Function that scans the DOM tree for header elements (the DOM2
|
|
|
|
|
// nodeIterator API would be a better technique but not supported by all
|
|
|
|
|
// browsers).
|
|
|
|
|
var iterate = function (el) {
|
|
|
|
|
for (var i = el.firstChild; i != null; i = i.nextSibling) {
|
|
|
|
|
if (i.nodeType == 1 /* Node.ELEMENT_NODE */) {
|
|
|
|
|
var mo = re.exec(i.tagName)
|
|
|
|
|
if (mo)
|
|
|
|
|
result[result.length] = new TocEntry(i, getText(i), mo[1]-1);
|
|
|
|
|
iterate(i);
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
iterate(el);
|
|
|
|
|
return result;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// This function does the work. toclevels = 1..4.
|
|
|
|
|
function generateToc(toclevels) {
|
|
|
|
|
var toc = document.getElementById("toc");
|
|
|
|
|
var entries = tocEntries(document.getElementsByTagName("body")[0], toclevels);
|
|
|
|
|
for (var i = 0; i < entries.length; ++i) {
|
|
|
|
|
var entry = entries[i];
|
|
|
|
|
if (entry.element.id == "")
|
|
|
|
|
entry.element.id = "toc" + i;
|
|
|
|
|
var a = document.createElement("a");
|
|
|
|
|
a.href = "#" + entry.element.id;
|
|
|
|
|
a.appendChild(document.createTextNode(entry.text));
|
|
|
|
|
var div = document.createElement("div");
|
|
|
|
|
div.appendChild(a);
|
|
|
|
|
div.className = "toclevel" + entry.toclevel;
|
|
|
|
|
toc.appendChild(div);
|
|
|
|
|
}
|
2008-12-05 16:44:33 +03:00
|
|
|
if (entries.length == 0)
|
|
|
|
|
document.getElementById("header").removeChild(toc);
|
2008-09-03 15:38:45 +04:00
|
|
|
}
|
|
|
|
|
/*]]>*/
|
|
|
|
|
</script>
|
|
|
|
|
<title>CSYNC User Guide</title>
|
|
|
|
|
</head>
|
|
|
|
|
<body>
|
|
|
|
|
<div id="header">
|
|
|
|
|
<h1>CSYNC User Guide</h1>
|
|
|
|
|
<span id="author">Andreas Schneider</span><br />
|
|
|
|
|
<span id="email"><tt><<a href="mailto:mail@cynapses.org">mail@cynapses.org</a>></tt></span><br />
|
|
|
|
|
<div id="toc">
|
|
|
|
|
<div id="toctitle">Table of Contents</div>
|
|
|
|
|
<noscript><p><b>JavaScript must be enabled in your browser to display the table of contents.</b></p></noscript>
|
|
|
|
|
</div>
|
|
|
|
|
</div>
|
|
|
|
|
<div id="preamble">
|
|
|
|
|
<div class="sectionbody">
|
2008-12-05 16:44:33 +03:00
|
|
|
<div class="para"><p>csync is a bidirectional file synchronizer for Linux and allows to keep two
|
|
|
|
|
copies of files and directories in sync. It uses uses widly adopted protocols
|
|
|
|
|
like smb or sftp so that there is no need for a server component of csync. It
|
|
|
|
|
is a user-level program which means you don't need to be a superuser.</p></div>
|
2008-09-03 15:38:45 +04:00
|
|
|
</div>
|
|
|
|
|
</div>
|
|
|
|
|
<h2 id="_introduction">1. Introduction</h2>
|
|
|
|
|
<div class="sectionbody">
|
|
|
|
|
<div class="para"><p>It is often the case that we have multiple copies (called replicas) of a
|
|
|
|
|
filesystem or part of a filesystem (for example on a notebook and on a desktop
|
2008-09-05 18:54:48 +04:00
|
|
|
computer). Changes to each replica are often made independently and as a
|
|
|
|
|
result they do not contain the same information. In that case a file
|
|
|
|
|
synchronizer is used to make them consistent again, without loosing any
|
|
|
|
|
information.</p></div>
|
|
|
|
|
<div class="para"><p>The goal is to detect conflicting <a href="#X13">updates</a> (files which has been
|
|
|
|
|
modified) and propagate non-conflicting updates to each replica. If there
|
|
|
|
|
are no conflicts left we are done and the replicas are identical.</p></div>
|
2008-09-03 15:38:45 +04:00
|
|
|
</div>
|
|
|
|
|
<h2 id="_basics">2. Basics</h2>
|
|
|
|
|
<div class="sectionbody">
|
2008-09-05 18:54:48 +04:00
|
|
|
<div class="para"><p>This section describes some basics you might need to understand how file
|
|
|
|
|
synchronization works.</p></div>
|
2008-09-03 15:38:45 +04:00
|
|
|
<h3 id="_paths">2.1. Paths</h3><div style="clear:left"></div>
|
2008-09-05 18:54:48 +04:00
|
|
|
<div class="para"><p>A path normally refers to a point with a set of files which should be
|
|
|
|
|
synchronized. It is specified relative to the root of the replica. The path is
|
|
|
|
|
just a sequence of names separated by <em>/</em>.</p></div>
|
|
|
|
|
<div class="admonitionblock">
|
|
|
|
|
<table><tr>
|
|
|
|
|
<td class="icon">
|
|
|
|
|
<img src="./images/icons/note.png" alt="Note" />
|
|
|
|
|
</td>
|
|
|
|
|
<td class="content">The path separator is always a forward slash <em>/</em>, even for Windows.</td>
|
|
|
|
|
</tr></table>
|
|
|
|
|
</div>
|
|
|
|
|
<div class="para"><p>csync is always using the absolute path. This could be <em>/home/gladiac</em> or
|
|
|
|
|
for sftp <em>sftp://gladiac:secret@myserver/home/gladiac</em>.</p></div>
|
2008-09-03 15:38:45 +04:00
|
|
|
<h3 id="X13">2.2. What is an update?</h3><div style="clear:left"></div>
|
2008-09-05 18:54:48 +04:00
|
|
|
<div class="para"><p>The contents of a path could be a file, a directory or a symbolic link
|
|
|
|
|
(symbolic links are not supported yet). To be more precise, if the path refers
|
|
|
|
|
to:</p></div>
|
|
|
|
|
<div class="ilist"><ul>
|
|
|
|
|
<li>
|
|
|
|
|
<p>
|
|
|
|
|
a regular file, the the contents of the file are the byte stream and the
|
|
|
|
|
metatdata of the file.
|
|
|
|
|
</p>
|
|
|
|
|
</li>
|
|
|
|
|
<li>
|
|
|
|
|
<p>
|
|
|
|
|
a directory, then the content is the metadata of the directory.
|
|
|
|
|
</p>
|
|
|
|
|
</li>
|
|
|
|
|
<li>
|
|
|
|
|
<p>
|
|
|
|
|
a symbolic link, then the content is the string where the link points to.
|
|
|
|
|
</p>
|
|
|
|
|
</li>
|
|
|
|
|
</ul></div>
|
|
|
|
|
<div class="para"><p>csync keeps a record of each path which has been successfully synchronized. The
|
|
|
|
|
path gets compared with the record and if it has changed since the last
|
|
|
|
|
synchronization, we have an update. This is done by comparing the modification
|
|
|
|
|
or change (modification time of the metadata) time.</p></div>
|
2008-09-03 15:38:45 +04:00
|
|
|
<h3 id="_what_is_a_conflict">2.3. What is a conflict?</h3><div style="clear:left"></div>
|
2008-09-05 18:54:48 +04:00
|
|
|
<div class="para"><p>A path is conflicting if it fulfills the following conditions:</p></div>
|
|
|
|
|
<div class="olist"><ol>
|
|
|
|
|
<li>
|
|
|
|
|
<p>
|
|
|
|
|
it has been updated in one replica,
|
|
|
|
|
</p>
|
|
|
|
|
</li>
|
|
|
|
|
<li>
|
|
|
|
|
<p>
|
|
|
|
|
it or any of its descendants has been updated on the other replica too, and
|
|
|
|
|
</p>
|
|
|
|
|
</li>
|
|
|
|
|
<li>
|
|
|
|
|
<p>
|
|
|
|
|
its contents in are not identical.
|
|
|
|
|
</p>
|
|
|
|
|
</li>
|
|
|
|
|
</ol></div>
|
2008-09-03 15:38:45 +04:00
|
|
|
</div>
|
|
|
|
|
<h2 id="_file_synchronization">3. File Synchronization</h2>
|
|
|
|
|
<div class="sectionbody">
|
2008-09-05 18:54:48 +04:00
|
|
|
<div class="para"><p>The main goal of a file synchronizer is correctness. It changes whole or
|
|
|
|
|
separated pieces of a users file system. So a user is not able to monitor the
|
|
|
|
|
complete file synchronization process. So the synchronizer is in a position
|
|
|
|
|
where it can damage the file system. It is important that the implementation
|
|
|
|
|
behaves correctly under all conditions, even if there is an unexpected error
|
|
|
|
|
(for example disk full).</p></div>
|
|
|
|
|
<div class="para"><p>On problem concerning correctness is the handling of conflicts. Each file
|
|
|
|
|
synchronizer tries to propagate conflicting changes to the other replica. At
|
|
|
|
|
the end both replicas should be identical. There are different strategies to
|
|
|
|
|
fulfill these goals.</p></div>
|
|
|
|
|
<div class="para"><p>csync is a 3-phase file synchronizer. The desicion for this design was that
|
|
|
|
|
user interaction should be possible and it should be easy to understand the
|
|
|
|
|
process. The 3 phases are update detection, reconciliation and propagation.
|
|
|
|
|
These will be described in the following sections.</p></div>
|
2008-09-03 15:38:45 +04:00
|
|
|
<h3 id="_update_detection">3.1. Update detection</h3><div style="clear:left"></div>
|
2008-09-05 18:54:48 +04:00
|
|
|
<div class="para"><p>There are differnt strategies to do update detection. csync uses a state-based
|
|
|
|
|
modtime-inode update detector. This means it uses a the modification time to
|
|
|
|
|
detect updates. It doesn't require much resources. A record of each file is
|
|
|
|
|
stored in a database (called statedb) and compared with the current
|
|
|
|
|
modification time during update detection. If the file has changed since the
|
|
|
|
|
last synchronization a instruction is set to evaluate it during the
|
|
|
|
|
reconcilation phase. If we don't have a record for a file we invastigate, it is
|
|
|
|
|
marked as new.</p></div>
|
2008-12-05 16:44:33 +03:00
|
|
|
<div class="para"><p>There is a problem to detect renaming of files. This is sovled by the record we
|
2008-09-05 18:54:48 +04:00
|
|
|
store in the statedb too. If we don't find the file by the name in the database
|
|
|
|
|
we search for the inode number. If the inode number is found then the file has
|
|
|
|
|
been renamed.</p></div>
|
2008-09-03 15:38:45 +04:00
|
|
|
<h3 id="_reconciliation">3.2. Reconciliation</h3><div style="clear:left"></div>
|
2008-12-05 16:44:33 +03:00
|
|
|
<div class="para"><p>The most improtant component is the update detector cause the reconciler depends
|
|
|
|
|
on it. The correctness of reconciler is mandatory cause it can damage a
|
|
|
|
|
filesystem. It decides which file:</p></div>
|
|
|
|
|
<div class="ilist"><ul>
|
|
|
|
|
<li>
|
|
|
|
|
<p>
|
|
|
|
|
keeps untouched
|
|
|
|
|
</p>
|
|
|
|
|
</li>
|
|
|
|
|
<li>
|
|
|
|
|
<p>
|
|
|
|
|
has a conflict
|
|
|
|
|
</p>
|
|
|
|
|
</li>
|
|
|
|
|
<li>
|
|
|
|
|
<p>
|
|
|
|
|
gets synchronized
|
|
|
|
|
</p>
|
|
|
|
|
</li>
|
|
|
|
|
<li>
|
|
|
|
|
<p>
|
|
|
|
|
or gets <strong>deleted</strong>
|
|
|
|
|
</p>
|
|
|
|
|
</li>
|
|
|
|
|
</ul></div>
|
|
|
|
|
<div class="para"><p>A wrong decision of the reconciler leads in most cases to a loss of data. So there
|
|
|
|
|
are several conditions a the file synchronizer has to follow.</p></div>
|
|
|
|
|
<h4 id="_specification">3.2.1. Specification</h4>
|
2008-09-03 15:38:45 +04:00
|
|
|
<div class="para"><p>TODO</p></div>
|
|
|
|
|
<h3 id="_propagation">3.3. Propagation</h3><div style="clear:left"></div>
|
2008-12-05 16:44:33 +03:00
|
|
|
<div class="para"><p>The next instance of the file synchronizer the propagator. It uses the
|
|
|
|
|
calculated records to apply them on the current replica.</p></div>
|
|
|
|
|
<div class="ilist"><ul>
|
|
|
|
|
<li>
|
|
|
|
|
<p>
|
|
|
|
|
2-phase-copy
|
|
|
|
|
</p>
|
|
|
|
|
</li>
|
|
|
|
|
<li>
|
|
|
|
|
<p>
|
|
|
|
|
merge trees and write journal
|
|
|
|
|
</p>
|
|
|
|
|
</li>
|
|
|
|
|
</ul></div>
|
|
|
|
|
<h3 id="_robustness">3.4. Robustness</h3><div style="clear:left"></div>
|
|
|
|
|
<div class="para"><p>TODO</p></div>
|
|
|
|
|
<h4 id="_crash_resistance">3.4.1. Crash resistance</h4>
|
|
|
|
|
<div class="para"><p>TODO</p></div>
|
|
|
|
|
<h4 id="_transfer_errors">3.4.2. Transfer errors</h4>
|
|
|
|
|
<div class="para"><p>TODO</p></div>
|
|
|
|
|
<h4 id="_database_loss">3.4.3. Database loss</h4>
|
2008-09-03 15:38:45 +04:00
|
|
|
<div class="para"><p>TODO</p></div>
|
|
|
|
|
</div>
|
|
|
|
|
<h2 id="_getting_started">4. Getting started</h2>
|
|
|
|
|
<div class="sectionbody">
|
|
|
|
|
<h3 id="_installing_csync">4.1. Installing csync</h3><div style="clear:left"></div>
|
|
|
|
|
<div class="para"><p>See the <tt>README</tt> and <tt>INSTALL</tt> files for install prerequisites and
|
|
|
|
|
procedures. Packagers take a look at <a href="#X90">Appendix B: Packager Notes</a>.</p></div>
|
|
|
|
|
<h3 id="_using_the_commandline_client">4.2. Using the commandline client</h3><div style="clear:left"></div>
|
|
|
|
|
<div class="para"><p>TODO
|
|
|
|
|
csync /home/csync sftp://TODO:secret@server:port/profile/TODO</p></div>
|
|
|
|
|
<h3 id="_the_pam_module">4.3. The PAM module</h3><div style="clear:left"></div>
|
|
|
|
|
<div class="para"><p>TODO</p></div>
|
|
|
|
|
</div>
|
|
|
|
|
<h2 id="X90">5. Appendix A: Packager Notes</h2>
|
|
|
|
|
<div class="sectionbody">
|
|
|
|
|
<div class="para"><p>Read the <tt>README</tt> and <tt>INSTALL</tt> files (in the distribution root
|
|
|
|
|
directory).</p></div>
|
|
|
|
|
</div>
|
|
|
|
|
<div id="footer">
|
|
|
|
|
<div id="footer-text">
|
2008-12-05 16:44:33 +03:00
|
|
|
Last updated 2008-11-20 12:16:02 CEST
|
2008-09-03 15:38:45 +04:00
|
|
|
</div>
|
|
|
|
|
</div>
|
|
|
|
|
</body>
|
|
|
|
|
</html>
|
