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<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>Overview</title><link rel="stylesheet" href="styles.css" type="text/css" /><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /><link rel="start" href="index.html" title="Version Control with Subversion" /><link rel="up" href="svn.serverconfig.html" title="Chapter 6. Server Configuration" /><link rel="prev" href="svn.serverconfig.html" title="Chapter 6. Server Configuration" /><link rel="next" href="svn.serverconfig.choosing.html" title="Choosing a Server Configuration" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Overview</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="svn.serverconfig.html">Prev</a> </td><th width="60%" align="center">Chapter 6. Server Configuration</th><td width="20%" align="right"> <a accesskey="n" href="svn.serverconfig.choosing.html">Next</a></td></tr></table><hr /></div><div class="sect1" lang="en" xml:lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="svn.serverconfig.overview"></a>Overview</h2></div></div></div><p>Subversion was designed with an abstract network layer.
This means that a repository can be programmatically accessed by
any sort of server process, and the client “<span class="quote">repository
access</span>” API allows programmers to write plugins that
speak relevant network protocols. In theory, Subversion can use
an infinite number of network implementations. In practice,
there are only two servers at the time of this writing.</p><p>Apache is an extremely popular webserver; using the
<span class="command"><strong>mod_dav_svn</strong></span> module, Apache can access a
repository and make it available to clients via the
WebDAV/DeltaV protocol, which is an extension of HTTP. Because
Apache is an extremely extensible web server, it provides a
number of features “<span class="quote">for free</span>”, such as encrypted
SSL communication, logging, integration with a number of
third-party authentication systems, and limited built-in web
browsing of repositories.</p><p>In the other corner is <span class="command"><strong>svnserve</strong></span>: a small,
lightweight server program that speaks a custom protocol with
clients. Because its protocol is explicitly designed for
Subversion and is stateful (unlike HTTP), it provides
significantly faster network operations—but at the cost of
some features as well. While it can use SASL to provide a
variety of authentication and encryption options, it has no
logging or built-in web-browsing. It is, however, extremely
easy to set up and is often the best option for small teams just
starting out with Subversion.</p><p>A third option is to use <span class="command"><strong>svnserve</strong></span>
tunneled over an SSH connection. Even though this scenario
still uses <span class="command"><strong>svnserve</strong></span>, it differs quite a bit
in features from a traditional <span class="command"><strong>svnserve</strong></span>
deployment. SSH is used to encrypt all communication. SSH is
also used exclusively to authenticate, so real system accounts
are required on the server host (unlike
vanilla <span class="command"><strong>svnserve</strong></span>, which has its own private
user accounts.) Finally, because this setup requires that each
user spawn a private, temporary <span class="command"><strong>svnserve</strong></span>
process, it's equivalent (from a permissions point of view) to
allowing a group of local users to all access the repository
via <code class="literal">file://</code> URLs. Path-based access control
has no meaning, since each user is accessing the repository
database files directly.</p><p>Here's a quick summary of the three typical server
deployments.</p><div class="table"><a id="svn.serverconfig.overview.tbl-1"></a><p class="title"><b>Table 6.1. Comparison of Subversion Server Options</b></p><div class="table-contents"><table summary="Comparison of Subversion Server Options" border="1"><colgroup><col /><col /><col /><col /></colgroup><thead><tr><th>Feature</th><th>Apache + mod_dav_svn</th><th>svnserve</th><th>svnserve over SSH</th></tr></thead><tbody><tr><td>Authentication options</td><td>HTTP(S) basic auth, X.509 certificates, LDAP, NTLM, or
any other mechanism available to Apache httpd</td><td>CRAM-MD5 by default; LDAP, NTLM, or any other mechanism
available to SASL</td><td>SSH</td></tr><tr><td>User account options</td><td>private 'users' file, or other mechanisms
available to Apache httpd (LDAP, SQL, etc.)</td><td>private 'users' file, or other mechanisms available
to SASL (LDAP, SQL, etc.)</td><td>system accounts</td></tr><tr><td>Authorization options</td><td>read/write access can be granted over whole
repository, or specified per-path.</td><td>read/write access can be granted over whole
repository, or specified per-path.</td><td>read/write access only grantable over whole
repository</td></tr><tr><td>Encryption</td><td>via optional SSL</td><td>via optional SASL features</td><td>SSH tunneled</td></tr><tr><td>Logging</td><td>full Apache logs of each HTTP request, with
optional “<span class="quote">high-level</span>” logging of general
client operations</td><td>no logging</td><td>no logging</td></tr><tr><td>Interoperability</td><td>partially usable by other WebDAV clients</td><td>only talks to svn clients</td><td>only talks to svn clients</td></tr><tr><td>Web viewing</td><td>limited built-in support, or via 3rd-party tools
such as ViewVC</td><td>only via 3rd-party tools such as ViewVC</td><td>only via 3rd-party tools such as ViewVC</td></tr><tr><td>Master-slave server replication</td><td>Transparent write-proxying available from slave to master</td><td>Can only create read-only slave servers</td><td>Can only create read-only slave servers</td></tr><tr><td>Speed</td><td>somewhat slower</td><td>somewhat faster</td><td>somewhat faster</td></tr><tr><td>Initial setup</td><td>somewhat complex</td><td>extremely simple</td><td>moderately simple </td></tr></tbody></table></div></div><br class="table-break" /></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="svn.serverconfig.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="svn.serverconfig.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="svn.serverconfig.choosing.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter 6. Server Configuration </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Choosing a Server Configuration</td></tr></table></div></body></html>
