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-<!-- $Revision: 1.31 $ -->
+<!-- $Revision: 1.32 $ -->
<!--
Copyright 2002-2004 The Apache Software Foundation
<em>different</em> pre-forked server processes. Here an inter-process cache
helps to avoid unneccessary session handshakes.</p>
<p>
-The following two storage <em>type</em>s are currently supported:</p>
+The following four storage <em>type</em>s are currently supported:</p>
<ul>
<li><code>none</code>
- <p>
- This is the default and just disables the global/inter-process Session
- Cache. There is no drawback in functionality, but a noticeable speed
- penalty can be observed.</p></li>
+
+ <p>This disables the global/inter-process Session Cache. This
+ will incur a noticeable speed penalty and may cause problems if
+ using certain browsers, particularly if client certificates are
+ enabled. This setting is not recommended.</p></li>
+
<li><code>dbm:/path/to/datafile</code>
- <p>
- This makes use of a DBM hashfile on the local disk to synchronize the
- local OpenSSL memory caches of the server processes. The slight increase
- in I/O on the server results in a visible request speedup for your
- clients, so this type of storage is generally recommended.</p></li>
+
+ <p>This makes use of a DBM hashfile on the local disk to
+ synchronize the local OpenSSL memory caches of the server
+ processes. This session cache may suffer reliability issues under
+ high load.</p></li>
+
<li><code>shm:/path/to/datafile</code>[<code>(</code><em>size</em><code>)</code>]
- <p>
- This makes use of a high-performance hash table (approx. <em>size</em> bytes
- in size) inside a shared memory segment in RAM (established via
- <code>/path/to/datafile</code>) to synchronize the local OpenSSL memory
- caches of the server processes. This storage type is not available on all
- platforms.</p></li>
+
+ <p>This makes use of a high-performance cyclic buffer
+ (approx. <em>size</em> bytes in size) inside a shared memory
+ segment in RAM (established via <code>/path/to/datafile</code>) to
+ synchronize the local OpenSSL memory caches of the server
+ processes. This is the recommended session cache.</p></li>
+
+<li><code>dc:UNIX:/path/to/socket</code>
+
+ <p>This makes use of the <a
+ href="http://www.distcache.org/">distcache</a> distributed session
+ caching libraries. The argument should specify the location of
+ the server or proxy to be used using the distcache address syntax;
+ for example, <code>UNIX:/path/to/socket</code> specifies a UNIX
+ domain socket (typically a local dc_client proxy);
+ <code>IP:server.example.com:9001</code> specifies an IP
+ address.</p></li>
+
</ul>
<example><title>Examples</title>
SSLSessionCache dbm:/usr/local/apache/logs/ssl_gcache_data<br />