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116 lines
3.0 KiB
XML
116 lines
3.0 KiB
XML
<?xml version="1.0" encoding="iso-8859-1"?>
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<!DOCTYPE refentry PUBLIC "-//Samba-Team//DTD DocBook V4.2-Based Variant V1.0//EN" "http://www.samba.org/samba/DTD/samba-doc">
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<refentry id="vfs_preopen.8">
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<refmeta>
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<refentrytitle>vfs_preopen</refentrytitle>
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<manvolnum>8</manvolnum>
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<refmiscinfo class="source">Samba</refmiscinfo>
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<refmiscinfo class="manual">System Administration tools</refmiscinfo>
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<refmiscinfo class="version">3.6</refmiscinfo>
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</refmeta>
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<refnamediv>
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<refname>vfs_preopen</refname>
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<refpurpose>Hide read latencies for applications reading numbered files</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<cmdsynopsis>
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<command>vfs objects = preopen</command>
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</cmdsynopsis>
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</refsynopsisdiv>
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<refsect1>
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<title>DESCRIPTION</title>
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<para>This VFS module is part of the
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<citerefentry><refentrytitle>samba</refentrytitle>
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<manvolnum>7</manvolnum></citerefentry> suite.</para>
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<para>This module assists applications that want to read numbered
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files in sequence with very strict latency requirements. One area
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where this happens in video streaming applications that want to read
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one file per frame.</para>
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<para>When you use this module, a number of helper processes is
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started that speculatively open files and read a number of bytes to
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prime the file system cache, so that later on when the real
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application's request comes along, no disk access is necessary.</para>
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<para>This module is stackable.</para>
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</refsect1>
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<refsect1>
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<title>OPTIONS</title>
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<variablelist>
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<varlistentry>
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<term>preopen:names = /pattern/</term>
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<listitem>
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<para>
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preopen:names specifies the file name pattern which should
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trigger the preopen helpers to do their work. We assume that
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the files are numbered incrementally. So if your file names
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are numbered FRAME00000.frm FRAME00001.frm and so on you would
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list them as <command>preopen:names=/FRAME*.frm/</command>
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>preopen:num_bytes = BYTES</term>
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<listitem>
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<para>
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Specifies the number of bytes the helpers should speculatively
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read, defaults to 1.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>preopen:helpers = NUM-PROCS</term>
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<listitem>
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<para>
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Number of forked helper processes, defaults to 1.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>preopen:queuelen = NUM-FILES</term>
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<listitem>
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<para>
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Number of files that should be speculatively opened. Defaults
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to the 10 subsequent files.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1>
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<title>VERSION</title>
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<para>This man page is correct for version 3.3 of the Samba suite.
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</para>
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</refsect1>
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<refsect1>
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<title>AUTHOR</title>
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<para>The original Samba software and related utilities
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were created by Andrew Tridgell. Samba is now developed
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by the Samba Team as an Open Source project similar
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to the way the Linux kernel is developed.</para>
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<para>The PREOPEN VFS module was created with contributions from
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Volker Lendecke and the developers at IBM.
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</para>
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</refsect1>
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</refentry>
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