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<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Chapter�33.�Handling Large Directories</title><link rel="stylesheet" href="../samba.css" type="text/css"><meta name="generator" content="DocBook XSL Stylesheets V1.74.0"><link rel="home" href="index.html" title="The Official Samba 3.4.x HOWTO and Reference Guide"><link rel="up" href="optional.html" title="Part�III.�Advanced Configuration"><link rel="prev" href="SambaHA.html" title="Chapter�32.�High Availability"><link rel="next" href="cfgsmarts.html" title="Chapter�34.�Advanced Configuration Techniques"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter�33.�Handling Large Directories</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="SambaHA.html">Prev</a>�</td><th width="60%" align="center">Part�III.�Advanced Configuration</th><td width="20%" align="right">�<a accesskey="n" href="cfgsmarts.html">Next</a></td></tr></table><hr></div><div class="chapter" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="largefile"></a>Chapter�33.�Handling Large Directories</h2></div><div><div class="author"><h3 class="author"><span class="firstname">Jeremy</span> <span class="orgname">Samba Team</span> <span class="surname">Allison</span></h3><div class="affiliation"><span class="orgname">Samba Team<br></span><div class="address"><p><code class="email"><<a class="email" href="mailto:jra@samba.org">jra@samba.org</a>></code></p></div></div></div></div><div><div class="author"><h3 class="author"><span class="firstname">John</span> <span class="othername">H.</span> <span class="orgname">Samba Team</span> <span class="surname">Terpstra</span></h3><div class="affiliation"><span class="orgname">Samba Team<br></span><div class="address"><p><code class="email"><<a class="email" href="mailto:jht@samba.org">jht@samba.org</a>></code></p></div></div></div></div><div><p class="pubdate">March 5, 2005</p></div></div></div><p>

Samba-3.0.12 and later implements a solution for sites that have experienced performance degradation due to the

problem of using Samba-3 with applications that need large numbers of files (100,000 or more) per directory.

</p><p>

The key was fixing the directory handling to read only the current list requested instead of the old

(up to samba-3.0.11) behavior of reading the entire directory into memory before doling out names.

Normally this would have broken OS/2 applications, which have very strange delete semantics, but by

stealing logic from Samba4 (thanks, Tridge), the current code in 3.0.12 handles this correctly.

</p><p>

To set up an application that needs large numbers of files per directory in a way that does not

damage performance unduly, follow these steps:

</p><p>

First, you need to canonicalize all the files in the directory to have one case, upper or lower take your

pick (I chose upper because all my files were already uppercase names). Then set up a new custom share for the

application as follows:

</p><table class="simplelist" border="0" summary="Simple list"><tr><td> </td></tr><tr><td><em class="parameter"><code>[bigshare]</code></em></td></tr><tr><td><a class="indexterm" name="id2673469"></a><em class="parameter"><code>path = /data/manyfilesdir</code></em></td></tr><tr><td><a class="indexterm" name="id2673481"></a><em class="parameter"><code>read only = no</code></em></td></tr><tr><td><a class="indexterm" name="id2673493"></a><em class="parameter"><code>case sensitive = True</code></em></td></tr><tr><td><a class="indexterm" name="id2673504"></a><em class="parameter"><code>default case = upper</code></em></td></tr><tr><td><a class="indexterm" name="id2673516"></a><em class="parameter"><code>preserve case = no</code></em></td></tr><tr><td><a class="indexterm" name="id2673528"></a><em class="parameter"><code>short preserve case = no</code></em></td></tr></table><p>

</p><p>

Of course, use your own path and settings, but set the case options to match the case of all the files in your

directory. The path should point at the large directory needed for the application any new files created in

there and in any paths under it will be forced by smbd into uppercase, but smbd will no longer have to scan

the directory for names: it knows that if a file does not exist in uppercase, then it doesn't exist at all.

</p><p>

The secret to this is really in the <a class="link" href="smb.conf.5.html#CASESENSITIVE" target="_top">case sensitive = True</a>

line. This tells smbd never to scan for case-insensitive versions of names. So if an application asks for a file

called <code class="filename">FOO</code>, and it cannot be found by a simple stat call, then smbd will return file not

found immediately without scanning the containing directory for a version of a different case. The other

<code class="filename">xxx case xxx</code> lines make this work by forcing a consistent case on all files created by

<span class="application">smbd</span>.

</p><p>

Remember, all files and directories under the <em class="parameter"><code>path</code></em> directory must be in uppercase

with this <code class="filename">smb.conf</code> stanza because <span class="application">smbd</span> will not be able to find lowercase filenames with these settings. Also

note that this is done on a per-share basis, allowing this parameter to be set only for a share servicing an application with

this problematic behavior (using large numbers of entries in a directory) the rest of your <span class="application">smbd</span> shares

don't need to be affected.

</p><p>

This makes smbd much faster when dealing with large directories. My test case has over 100,000 files, and

smbd now deals with this very efficiently.

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